fix(ci): replace gh pr CLI with Gitea v1 REST in workflows + scripts (#75 class A)

Part of the post-#66 sweep to remove `gh` CLI dependencies that fail
silently against Gitea (which exposes /api/v1 only — no GraphQL → 405,
no /api/v3 → 404). Class A covers `gh pr list / view / diff / comment`
shapes.

Affected:

- `.github/workflows/auto-tag-runtime.yml`
  Replaced `gh pr list --search SHA --json number,labels` with a curl
  to `/api/v1/repos/.../pulls?state=closed&sort=newest&limit=50` +
  jq filter on `merge_commit_sha == github.sha`. Same end-to-end
  behaviour: locate the merged PR for this push, read its labels,
  pick the bump kind. Defensive `?.name // empty` jq guard handles
  unlabelled PRs without erroring. The 50-PR window is comfortably
  larger than the volume of staging→main promotes that close in any
  reasonable detection window.

- `scripts/check-stale-promote-pr.sh`
  Rewrote `fetch_prs` and `post_comment` to call Gitea's REST API
  directly. Gitea doesn't expose GitHub's compound `mergeStateStatus`
  / `reviewDecision` fields, so the new fetcher pulls
  `/pulls?state=open&base=main` then for each PR pulls
  `/pulls/{n}/reviews` and synthesizes the GitHub-shape JSON the rest
  of the script (and the existing fixture-based unit tests) consume:
    BLOCKED + REVIEW_REQUIRED  ↔ mergeable=true AND 0 APPROVED reviews
    DIRTY                      ↔ mergeable=false (alarm doesn't fire)
    CLEAN + APPROVED           ↔ mergeable=true AND ≥1 APPROVED review
  Comment-posting moves to `POST /repos/.../issues/{n}/comments`
  (Gitea treats PRs as issues for the comment surface, same as
  GitHub's REST). All 23 fixture-driven unit tests still pass —
  fixtures pass GitHub-shape JSON via PR_FIXTURE which short-circuits
  the live fetch path.

- `scripts/ops/check_migration_collisions.py`
  Replaced `gh pr list` + `gh pr diff` calls with stdlib `urllib`
  against /api/v1. Helper `_gitea_get` centralizes auth + error
  handling; uses GITEA_TOKEN env, falling back to GITHUB_TOKEN
  (act_runner) and GH_TOKEN. Return shape from
  `open_prs_with_migration_prefix` mimics the historical
  `--json number,headRefName` so the call sites are unchanged. All 9
  regex-classifier unit tests still pass; live integration test
  against the production Gitea API returns 0 collisions for prefix=999
  as expected.

curl invocation pattern is `curl --fail-with-body -sS` (NOT `-fsS` —
the two short-fail flags are mutually exclusive in modern curl;
caught by `curl: You must select either --fail or --fail-with-body,
not both` during local verification).

Token model: workflows pass act_runner's GITHUB_TOKEN (per-run, repo
read scope) — same surface used by the auto-sync fix in PR #66 plus
the surrounding workflows. No new repo secrets required.

Verification: bash unit tests (23/23 pass), python unittest (9/9 pass),
live curl call against production Gitea returns 200 with the expected
shape, YAML / shell / Python syntax all validate.

Closes part of #75. Other classes (D — `gh api`; F — `gh run list`)
land in follow-up PRs.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/auto-tag-runtime.yml

@@ -57,17 +57,42 @@ jobs:
         id: bump
         if: steps.skip.outputs.skip != 'true'
         env:
-          GH_TOKEN: ${{ github.token }}
+          # Gitea-shape token (act_runner forwards GITHUB_TOKEN as a
+          # short-lived per-run secret with read access to this repo).
+          # We hit `/api/v1/repos/.../pulls?state=closed` directly
+          # because `gh pr list` calls Gitea's GraphQL endpoint, which
+          # returns HTTP 405 (issue #75 / post-#66 sweep).
+          GITEA_TOKEN: ${{ github.token }}
+          REPO: ${{ github.repository }}
+          GITEA_API_URL: ${{ github.server_url }}/api/v1
+          PUSH_SHA: ${{ github.sha }}
         run: |
-          # The merged PR for this push commit. `gh pr list --search` finds
+          # Find the merged PR whose merge_commit_sha matches this push.
-          # closed PRs whose merge commit matches; we take the first.
+          # Gitea's `/repos/{owner}/{repo}/pulls?state=closed` returns
-          PR=$(gh pr list --state merged --search "${{ github.sha }}" --json number,labels --jq '.[0]' 2>/dev/null || echo "")
+          # PRs sorted newest-first; we paginate up to 50 and jq-filter
+          # on `merge_commit_sha == PUSH_SHA`. Bounded — auto-tag fires
+          # per push to main, so the matching PR is always among the
+          # most recent closures. 50 is comfortably more than the
+          # ~10-20 staging→main promotes that close in any reasonable
+          # window.
+          set -euo pipefail
+          PRS_JSON=$(curl --fail-with-body -sS \
+            -H "Authorization: token ${GITEA_TOKEN}" \
+            -H "Accept: application/json" \
+            "${GITEA_API_URL}/repos/${REPO}/pulls?state=closed&sort=newest&limit=50" \
+            2>/dev/null || echo "[]")
+          PR=$(printf '%s' "$PRS_JSON" \
+            | jq -c --arg sha "$PUSH_SHA" \
+                '[.[] | select(.merged_at != null and .merge_commit_sha == $sha)] | .[0] // empty')
           if [ -z "$PR" ] || [ "$PR" = "null" ]; then
-            echo "No merged PR found for ${{ github.sha }} — defaulting to patch bump."
+            echo "No merged PR found for ${PUSH_SHA} — defaulting to patch bump."
             echo "kind=patch" >> "$GITHUB_OUTPUT"
             exit 0
           fi
-          LABELS=$(echo "$PR" | jq -r '.labels[].name')
+          # Gitea returns labels under `.labels[].name`, same shape as
+          # GitHub's REST. The previous `gh pr list --json number,labels`
+          # output was identical; jq filter unchanged.
+          LABELS=$(printf '%s' "$PR" | jq -r '.labels[]?.name // empty')
           if echo "$LABELS" | grep -qx 'release:major'; then
             echo "kind=major" >> "$GITHUB_OUTPUT"
           elif echo "$LABELS" | grep -qx 'release:minor'; then

scripts/check-stale-promote-pr.sh

@@ -17,12 +17,23 @@
 #
 # Used by .github/workflows/auto-promote-stale-alarm.yml. Logic lives
 # here (not inline in the workflow YAML) so we can:
-#   - Unit-test it with a stubbed `gh` (see test-check-stale-promote-pr.sh)
+#   - Unit-test it with a fixture (see test-check-stale-promote-pr.sh)
 #   - Run it ad-hoc by an operator: `scripts/check-stale-promote-pr.sh`
 #   - Reuse the same surface in any sibling workflow that needs the same
 #     check (SSOT — one detector, many callers).
 #
-# Requires: `gh` CLI, `jq`. `GH_TOKEN` env in the workflow context.
+# Requires: `curl`, `jq`. `GITEA_TOKEN` (or `GITHUB_TOKEN` / `GH_TOKEN`
+# for back-compat) in the workflow context. Reads `GITHUB_SERVER_URL`
+# / `GITEA_API_URL` for the Gitea base, defaulting to
+# https://git.moleculesai.app/api/v1.
+#
+# Post-2026-05-06 (Gitea migration, issue #75): the previous version
+# called `gh pr list/view/comment`, all of which hit GitHub.com's
+# GraphQL or /api/v3 REST shapes. Gitea exposes /api/v1/ only (no
+# GraphQL → 405, no /api/v3 → 404). So this script now talks to the
+# Gitea v1 API directly via curl. The fixture-driven unit tests are
+# unchanged — they bypass the live fetch via PR_FIXTURE and still pass
+# the historical (GitHub-shape) JSON which `detect_stale` consumes.
 
 set -euo pipefail
 
@@ -36,14 +47,15 @@ set -euo pipefail
 # alarming. Override via env for tests + edge ops.
 STALE_HOURS="${STALE_HOURS:-4}"
 
-# Repo defaults to the current `gh` context. Tests pass --repo explicitly.
+# Repo defaults to GITHUB_REPOSITORY (act_runner sets this in workflow
+# context). Tests pass --repo explicitly.
 REPO="${GITHUB_REPOSITORY:-}"
 
 # Whether to post a comment to the PR. Off by default to avoid noise on
 # manual ad-hoc runs; the cron workflow turns it on.
 POST_COMMENT="${POST_COMMENT:-false}"
 
-# Where to read the open-PR JSON from. Empty = call `gh` live. Tests
+# Where to read the open-PR JSON from. Empty = call Gitea live. Tests
 # point this at a fixture file.
 PR_FIXTURE="${PR_FIXTURE:-}"
 
@@ -51,6 +63,17 @@ PR_FIXTURE="${PR_FIXTURE:-}"
 # the staleness math is deterministic.
 NOW_OVERRIDE="${NOW_OVERRIDE:-}"
 
+# Gitea API base. act_runner forwards github.server_url as
+# GITHUB_SERVER_URL; for the molecule-ai fleet that's
+# https://git.moleculesai.app. Append /api/v1 to get the REST root.
+# Override directly via GITEA_API_URL for tests / non-default hosts.
+GITEA_API_URL="${GITEA_API_URL:-${GITHUB_SERVER_URL:-https://git.moleculesai.app}/api/v1}"
+
+# Token. Workflow context sets GITHUB_TOKEN; we accept GITEA_TOKEN as
+# the explicit name and GH_TOKEN for back-compat with operator habits
+# from the GitHub era. First non-empty wins.
+GITEA_TOKEN="${GITEA_TOKEN:-${GITHUB_TOKEN:-${GH_TOKEN:-}}}"
+
 while [ $# -gt 0 ]; do
   case "$1" in
     --repo) REPO="$2"; shift 2 ;;
@@ -83,7 +106,7 @@ now_epoch() {
   fi
 }
 
-# Parse RFC3339 timestamps the way GitHub emits them (e.g.
+# Parse RFC3339 timestamps the way Gitea / GitHub emit them (e.g.
 # "2026-05-05T23:15:00Z"). gnu-date uses -d, bsd-date uses -j -f. Cover
 # both because the workflow runs on ubuntu-latest (gnu) but operators
 # may run this script on macOS (bsd).
@@ -106,14 +129,100 @@ to_epoch() {
 # Fetch open auto-promote PRs
 # -----------------------------------------------------------------------------
 
+# Gitea v1 returns PRs with the canonical Gitea shape (number, title,
+# created_at, html_url, mergeable, state). The previous GitHub-CLI
+# version returned a derived `mergeStateStatus` / `reviewDecision`
+# pair which only GitHub computes — Gitea doesn't expose them
+# natively. Rebuild equivalents:
+#
+#   mergeStateStatus = BLOCKED  ↔ Gitea: state==open AND mergeable==true
+#                                  AND no APPROVED review yet
+#                                  (i.e. branch protection is gating
+#                                  the auto-merge pending an approval)
+#   reviewDecision   = REVIEW_REQUIRED  ↔ Gitea: 0 APPROVED reviews
+#
+# This mirrors the SAME silent-block failure mode the GitHub version
+# detected: auto-merge armed, branch protection requires 1 review,
+# nobody's approved yet.
+#
+# Implementation: pull the open PR list base=main, then for each PR
+# pull /pulls/{n}/reviews and synthesize the GitHub-shape JSON the
+# rest of the script + the test fixtures consume.
 fetch_prs() {
   if [ -n "$PR_FIXTURE" ]; then
     cat "$PR_FIXTURE"
     return 0
   fi
-  gh pr list --repo "$REPO" \
+  if [ -z "$GITEA_TOKEN" ]; then
-    --base main --head staging --state open \
+    echo "::error::GITEA_TOKEN / GITHUB_TOKEN unset — cannot fetch PRs from $GITEA_API_URL" >&2
-    --json number,title,createdAt,mergeStateStatus,reviewDecision,url
+    return 1
+  fi
+  local prs_json
+  prs_json="$(curl --fail-with-body -sS \
+    -H "Authorization: token ${GITEA_TOKEN}" \
+    -H "Accept: application/json" \
+    "${GITEA_API_URL}/repos/${REPO}/pulls?state=open&base=main&limit=50" \
+    2>/dev/null)" || {
+    echo "::error::Failed to fetch PRs from ${GITEA_API_URL}/repos/${REPO}/pulls" >&2
+    return 1
+  }
+
+  # Filter to head=staging (the auto-promote shape) and synthesize
+  # mergeStateStatus + reviewDecision per PR. Approval count via
+  # /pulls/{n}/reviews. Errors fall through to 0-approvals (treated
+  # as REVIEW_REQUIRED) preserving the existing "fail-safe — alarm if
+  # uncertain" semantic.
+  local synthesized="[]"
+  while IFS= read -r pr; do
+    [ -z "$pr" ] && continue
+    [ "$pr" = "null" ] && continue
+    local num
+    num="$(printf '%s' "$pr" | jq -r '.number')"
+    [ -z "$num" ] && continue
+    [ "$num" = "null" ] && continue
+    local approved_count
+    approved_count="$(curl --fail-with-body -sS \
+      -H "Authorization: token ${GITEA_TOKEN}" \
+      -H "Accept: application/json" \
+      "${GITEA_API_URL}/repos/${REPO}/pulls/${num}/reviews" 2>/dev/null \
+      | jq '[.[] | select(.state == "APPROVED" and (.dismissed // false) == false)] | length' \
+      2>/dev/null || echo 0)"
+    local mergeable
+    mergeable="$(printf '%s' "$pr" | jq -r '.mergeable')"
+    local merge_state="UNKNOWN"
+    local review_decision="REVIEW_REQUIRED"
+    if [ "$mergeable" = "true" ]; then
+      if [ "$approved_count" -ge 1 ]; then
+        merge_state="CLEAN"
+        review_decision="APPROVED"
+      else
+        # mergeable but no approving review — exactly the wedge state
+        # the alarm targets.
+        merge_state="BLOCKED"
+        review_decision="REVIEW_REQUIRED"
+      fi
+    else
+      # not mergeable (conflicts, behind, failed checks) — different
+      # failure mode, the author owns the fix; the alarm doesn't fire.
+      merge_state="DIRTY"
+      review_decision="REVIEW_REQUIRED"
+    fi
+    synthesized="$(printf '%s' "$synthesized" \
+      | jq -c --argjson pr "$pr" \
+              --arg ms "$merge_state" \
+              --arg rd "$review_decision" \
+              '. + [{
+                 number: $pr.number,
+                 title: $pr.title,
+                 createdAt: $pr.created_at,
+                 mergeStateStatus: $ms,
+                 reviewDecision: $rd,
+                 url: $pr.html_url
+              }]')"
+  done < <(printf '%s' "$prs_json" \
+    | jq -c '.[] | select(.head.ref == "staging")' 2>/dev/null)
+
+  printf '%s\n' "$synthesized"
 }
 
 # -----------------------------------------------------------------------------
@@ -171,18 +280,40 @@ post_comment() {
   if [ "$POST_COMMENT" != "true" ]; then
     return 0
   fi
+  if [ -z "$GITEA_TOKEN" ]; then
+    echo "::warning::GITEA_TOKEN unset — cannot post stale-alarm comment on PR #$pr_num" >&2
+    return 0
+  fi
   # Idempotency: only one alarm comment per PR. Look for the marker
-  # string in existing comments before posting a new one.
+  # string in existing comments before posting a new one. Gitea's
+  # /repos/{owner}/{repo}/issues/{n}/comments returns the same shape
+  # for issues + PRs (PRs are issues internally on Gitea, same as
+  # GitHub's REST).
   local existing
-  existing="$(gh pr view "$pr_num" --repo "$REPO" --json comments \
+  existing="$(curl --fail-with-body -sS \
-    --jq '.comments[] | select(.body | test("scripts/check-stale-promote-pr.sh per issue #2975")) | .databaseId' \
+    -H "Authorization: token ${GITEA_TOKEN}" \
+    -H "Accept: application/json" \
+    "${GITEA_API_URL}/repos/${REPO}/issues/${pr_num}/comments?limit=50" 2>/dev/null \
+    | jq -r '.[] | select(.body | test("scripts/check-stale-promote-pr.sh per issue #2975")) | .id' \
     | head -n1)"
   if [ -n "$existing" ]; then
     echo "::notice::PR #$pr_num already has a stale-alarm comment ($existing) — not re-posting"
     return 0
   fi
-  comment_body "$age_h" | gh pr comment "$pr_num" --repo "$REPO" --body-file -
+  local body
-  echo "::notice::Posted stale-alarm comment on PR #$pr_num (age=${age_h}h)"
+  body="$(comment_body "$age_h")"
+  if curl --fail-with-body -sS \
+      -X POST \
+      -H "Authorization: token ${GITEA_TOKEN}" \
+      -H "Accept: application/json" \
+      -H "Content-Type: application/json" \
+      "${GITEA_API_URL}/repos/${REPO}/issues/${pr_num}/comments" \
+      -d "$(jq -nc --arg b "$body" '{body: $b}')" \
+      >/dev/null 2>&1; then
+    echo "::notice::Posted stale-alarm comment on PR #$pr_num (age=${age_h}h)"
+  else
+    echo "::warning::Failed to POST stale-alarm comment on PR #$pr_num" >&2
+  fi
 }
 
 # -----------------------------------------------------------------------------

scripts/ops/check_migration_collisions.py

@@ -19,9 +19,15 @@ Exit codes:
     0  — no collisions
     1  — collision detected; output names the conflicting PR(s) for the author
 
-Designed to run from a GitHub Actions PR check. Reads PR metadata via the
+Designed to run from a Gitea Actions PR check. Reads PR metadata via direct
-GitHub CLI (gh) which is preinstalled on ubuntu-latest runners. Runs in
+HTTP calls to Gitea's REST API (`/api/v1/`), which on the molecule-ai fleet
-under 10s against a typical PR.
+lives at https://git.moleculesai.app. Runs in under 10s against a typical PR.
+
+Post-2026-05-06 (Gitea migration, issue #75): the previous version called
+the GitHub CLI (``gh pr list``, ``gh pr diff``). On Gitea those calls hit
+either the GraphQL endpoint (HTTP 405) or /api/v3 (HTTP 404). This module
+now talks to /api/v1 directly via urllib so it works against any Gitea
+host without a `gh` install or extra dependencies.
 """
 
 from __future__ import annotations
@@ -31,12 +37,70 @@ import os
 import re
 import subprocess
 import sys
+import urllib.error
+import urllib.parse
+import urllib.request
 from pathlib import Path
 
 MIGRATIONS_DIR = "workspace-server/migrations"
 MIGRATION_FILE_RE = re.compile(r"^(\d+)_[^/]+\.(up|down)\.sql$")
 
 
+def _gitea_api_url() -> str:
+    """Resolve the Gitea API base URL.
+
+    act_runner forwards github.server_url as GITHUB_SERVER_URL; for the
+    molecule-ai fleet that's https://git.moleculesai.app. Append /api/v1
+    to get the REST root. Override directly via GITEA_API_URL for tests
+    or non-default hosts.
+    """
+    env_override = os.environ.get("GITEA_API_URL", "").rstrip("/")
+    if env_override:
+        return env_override
+    server = os.environ.get("GITHUB_SERVER_URL", "https://git.moleculesai.app").rstrip("/")
+    return f"{server}/api/v1"
+
+
+def _gitea_token() -> str:
+    """Resolve the Gitea token from env. GITEA_TOKEN wins; falls back
+    to GITHUB_TOKEN (set by act_runner) and GH_TOKEN (operator habit
+    from the GitHub era)."""
+    return (
+        os.environ.get("GITEA_TOKEN")
+        or os.environ.get("GITHUB_TOKEN")
+        or os.environ.get("GH_TOKEN")
+        or ""
+    )
+
+
+def _gitea_get(path: str, params: dict[str, str] | None = None) -> bytes | None:
+    """GET against /api/v1; returns response body or None on HTTP error.
+
+    Errors return None (not raise) because callers handle missing data
+    by emitting an actionable workflow message rather than crashing the
+    PR check on a transient API blip.
+    """
+    base = _gitea_api_url()
+    qs = ""
+    if params:
+        qs = "?" + urllib.parse.urlencode(params)
+    url = f"{base}/{path.lstrip('/')}{qs}"
+    req = urllib.request.Request(url)
+    token = _gitea_token()
+    if token:
+        req.add_header("Authorization", f"token {token}")
+    req.add_header("Accept", "application/json")
+    try:
+        with urllib.request.urlopen(req, timeout=20) as resp:  # noqa: S310
+            return resp.read()
+    except urllib.error.HTTPError as e:
+        sys.stderr.write(f"Gitea API HTTP {e.code} on {path}: {e.reason}\n")
+        return None
+    except (urllib.error.URLError, TimeoutError) as e:
+        sys.stderr.write(f"Gitea API network error on {path}: {e}\n")
+        return None
+
+
 def run(cmd: list[str], check: bool = True) -> str:
     """Run a subprocess and return stdout. Raise on non-zero when check=True."""
     result = subprocess.run(cmd, capture_output=True, text=True)
@@ -96,32 +160,49 @@ def open_prs_with_migration_prefix(
     repo: str, prefix: int, exclude_pr: int
 ) -> list[dict]:
     """Return open PRs (other than `exclude_pr`) that add a migration with
-    `prefix`. Uses `gh pr diff` per PR — we only need to walk PRs that are
+    `prefix`. Walks open PRs via Gitea's `/repos/{owner}/{repo}/pulls` and
-    actually in flight, so the cost is bounded by open-PR count.
+    pulls each one's changed-file list via `/pulls/{n}/files`. The cost is
+    bounded by open-PR count, which is small (<100) on this repo. The
+    return shape mimics the GitHub CLI's `--json number,headRefName`:
+    ``[{"number": int, "headRefName": str}, ...]``.
     """
-    out = run([
+    body = _gitea_get(
-        "gh", "pr", "list", "--repo", repo, "--state", "open",
+        f"repos/{repo}/pulls",
-        "--json", "number,headRefName", "--limit", "100",
+        {"state": "open", "limit": "50"},
-    ])
+    )
-    prs = json.loads(out)
+    if body is None:
+        # Best-effort: a transient Gitea blip shouldn't fail the PR
+        # check (the base-branch collision check runs locally and is
+        # the more common failure mode).
+        return []
+    prs = json.loads(body)
     matches: list[dict] = []
     for pr in prs:
         num = pr["number"]
         if num == exclude_pr:
             continue
-        try:
+        # Gitea returns the head ref under .head.ref (REST shape);
-            files = run([
+        # GitHub CLI's --json headRefName flattens it. Normalize on
-                "gh", "pr", "diff", str(num), "--repo", repo, "--name-only",
+        # the way out so callers see the historical shape.
-            ], check=False)
+        head_ref_name = (pr.get("head") or {}).get("ref", "")
-        except Exception:  # noqa: BLE001
+        files_body = _gitea_get(f"repos/{repo}/pulls/{num}/files", {"limit": "100"})
+        if files_body is None:
             continue
-        for raw in files.splitlines():
+        try:
+            files = json.loads(files_body)
+        except json.JSONDecodeError:
+            continue
+        for f in files:
+            # Gitea's /pulls/{n}/files returns objects with `.filename`
+            # (same as GitHub's REST). Older Gitea versions emit
+            # `.name` instead — handle both.
+            raw = f.get("filename") or f.get("name") or ""
             path = Path(raw.strip())
             if not path.name:
                 continue
             m = MIGRATION_FILE_RE.match(path.name)
             if m and int(m.group(1)) == prefix:
-                matches.append(pr)
+                matches.append({"number": num, "headRefName": head_ref_name})
                 break
     return matches
 
@@ -138,7 +219,10 @@ def main() -> int:
     pr_number = int(pr_number_env)
     base_ref = os.environ.get("BASE_REF", "origin/staging")
     head_ref = os.environ.get("HEAD_REF", "HEAD")
-    repo = os.environ.get("GITHUB_REPOSITORY", "Molecule-AI/molecule-core")
+    # Default kept lowercase to match the Gitea-canonical org name
+    # (post-2026-05-06 migration). Tests + workflow context override
+    # via GITHUB_REPOSITORY which act_runner sets per-run.
+    repo = os.environ.get("GITHUB_REPOSITORY", "molecule-ai/molecule-core")
 
     added = migrations_in_diff(base_ref, head_ref)
     if not added: