fix(workspace-server): emit Gitea/PyPI URLs for external user instructions (RFC #229 P2-5)

The Molecule-AI GitHub org was suspended 2026-05-06; canonical SCM is
now git.moleculesai.app. external_connection.go was still emitting
github.com URLs in operator-facing copy-paste blocks, breaking
external-agent onboarding silently.

Per-site decisions (8 emit sites in 1 file):

- L124 (channel template doc comment): swap source-of-truth comment to
  Gitea host.
- L137 /plugin marketplace add Molecule-AI/...: swap to explicit Gitea
  HTTPS URL form. End-to-end-verified path per internal#37 § 1.A.
- L138 /plugin install molecule@molecule-mcp-claude-channel: marketplace
  name is molecule-channel (per remote .claude-plugin/marketplace.json),
  not the repo name. Fix to molecule@molecule-channel.
- L157 --channels plugin:molecule@molecule-mcp-claude-channel: same
  marketplace-name fix.
- L179 user-facing GitHub URL: swap to Gitea.
- L261 pip install git+https://github.com/Molecule-AI/molecule-sdk-python:
  not on PyPI; swap to git+https://git.moleculesai.app/molecule-ai/...
- L310 hermes-channel doc comment: swap source-of-truth comment.
- L339 pip install git+https://github.com/Molecule-AI/hermes-channel-molecule:
  not on PyPI; swap to Gitea.
- L369 issue-tracker URL: swap to Gitea.

Verification:
- molecule-ai-workspace-runtime, codex-channel-molecule are on PyPI (200);
  no swap needed for those pip lines (they were already package-name form).
- molecule-mcp-claude-channel, molecule-sdk-python, hermes-channel-molecule
  are NOT on PyPI; swapped to git+https://git.moleculesai.app/molecule-ai/
  form. All three repos are public on Gitea (default branch main) and
  serve git-upload-pack unauthenticated (verified curl 200 against
  /info/refs?service=git-upload-pack).
- Third-party github URLs (gin import, openai/codex, NousResearch/
  hermes-agent upstream issue trackers, npm @openai/codex) intentionally
  preserved.

Adds TestExternalTemplates_NoBrokenMoleculeAIGitHubURLs regression guard
to prevent the same broken URLs from re-emerging on future template
edits.

go vet / go build / existing TestExternal* — all clean.

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

workspace-server/internal/handlers/external_connection.go

@@ -121,7 +121,7 @@ curl -fsS -X POST "{{PLATFORM_URL}}/registry/register" \
 // operators whose external agent IS a Claude Code session (laptop or
 // remote dev VM); routes the workspace's A2A traffic into the running
 // Claude Code session as conversation turns via MCP. The plugin source
-// lives at github.com/Molecule-AI/molecule-mcp-claude-channel — polling
+// lives at git.moleculesai.app/molecule-ai/molecule-mcp-claude-channel — polling
 // based, no tunnel required (uses /workspaces/:id/activity?since_secs=,
 // platform-side support shipped in #2300).
 const externalChannelTemplate = `# Claude Code channel — bridges this workspace's A2A traffic into your
@@ -134,8 +134,8 @@ const externalChannelTemplate = `# Claude Code channel — bridges this workspac
 #    The plugin is NOT on Anthropic's default allowlist, so a one-time
 #    marketplace-add is needed before install:
 #
-#      /plugin marketplace add Molecule-AI/molecule-mcp-claude-channel
-#      /plugin install molecule@molecule-mcp-claude-channel
+#      /plugin marketplace add https://git.moleculesai.app/molecule-ai/molecule-mcp-claude-channel.git
+#      /plugin install molecule@molecule-channel
 #
 #    Then either run /reload-plugins or restart Claude Code so the
 #    plugin is registered.
@@ -154,7 +154,7 @@ chmod 600 ~/.claude/channels/molecule/.env
 #    flag to opt in — without it, you'll see "not on the approved channels
 #    allowlist" on startup.
 claude --dangerously-load-development-channels \
-  --channels plugin:molecule@molecule-mcp-claude-channel
+  --channels plugin:molecule@molecule-channel
 
 # You should see on stderr:
 #   molecule channel: connected — watching 1 workspace(s) at {{PLATFORM_URL}}
@@ -176,7 +176,7 @@ claude --dangerously-load-development-channels \
 # add the plugin to allowedChannelPlugins in claude.ai admin settings.
 #
 # Multi-workspace: comma-separate IDs and tokens (same order). See
-# https://github.com/Molecule-AI/molecule-mcp-claude-channel for
+# https://git.moleculesai.app/molecule-ai/molecule-mcp-claude-channel for
 # pairing flow, push-mode upgrade, and v0.2 roadmap.
 
 # Need help?
@@ -258,7 +258,7 @@ claude mcp add molecule -s user -- env \
 // externalPythonTemplate uses molecule-sdk-python's RemoteAgentClient +
 // A2AServer (PR #13 in that repo). Until the SDK cuts a v0.y release
 // to PyPI the snippet pins git+main.
-const externalPythonTemplate = `# pip install 'git+https://github.com/Molecule-AI/molecule-sdk-python.git@main'
+const externalPythonTemplate = `# pip install 'git+https://git.moleculesai.app/molecule-ai/molecule-sdk-python.git@main'
 
 import asyncio
 from molecule_agent import RemoteAgentClient, A2AServer
@@ -307,7 +307,7 @@ if __name__ == "__main__":
 // A2A traffic into the running hermes gateway as platform messages
 // via the molecule-channel plugin.
 //
-// The plugin (Molecule-AI/hermes-channel-molecule) is a hermes
+// The plugin (molecule-ai/hermes-channel-molecule on Gitea) is a hermes
 // platform adapter that:
 //   1. Spawns ``python -m molecule_runtime.a2a_mcp_server`` as a
 //      stdio MCP subprocess (separate from any hermes-side MCP
@@ -336,7 +336,7 @@ const externalHermesChannelTemplate = `# Hermes channel — bridges this workspa
 #
 # 1. Install the runtime + plugin:
 pip install molecule-ai-workspace-runtime
-pip install 'git+https://github.com/Molecule-AI/hermes-channel-molecule.git'
+pip install 'git+https://git.moleculesai.app/molecule-ai/hermes-channel-molecule.git'
 
 # 2. Export the workspace credentials:
 export MOLECULE_WORKSPACE_ID={{WORKSPACE_ID}}
@@ -366,7 +366,7 @@ hermes gateway --replace
 # by the plugin's molecule_runtime MCP subprocess).
 #
 # Source + issue tracker:
-# https://github.com/Molecule-AI/hermes-channel-molecule
+# https://git.moleculesai.app/molecule-ai/hermes-channel-molecule
 
 # Need help?
 #   Documentation: https://doc.moleculesai.app/docs/guides/external-agent-registration

workspace-server/internal/handlers/external_connection_test.go

@@ -75,3 +75,46 @@ func TestExternalMcpTemplates_UseMoleculeMcpWrapper(t *testing.T) {
 		}
 	}
 }
+
+// TestExternalTemplates_NoBrokenMoleculeAIGitHubURLs pins the invariant
+// that operator-facing snippets never embed github.com URLs pointing at
+// Molecule-AI repos.
+//
+// Why: the Molecule-AI GitHub org was suspended 2026-05-06 and the
+// canonical SCM is now git.moleculesai.app. Any `pip install
+// git+https://github.com/Molecule-AI/...` or marketplace-add Molecule-AI/
+// URL emitted to an external operator hits a 404 / org-suspended page,
+// breaking onboarding silently. RFC #229 P2-5.
+//
+// Third-party github URLs (gin, openai/codex, NousResearch/hermes-agent
+// upstream issue trackers, npm @openai/codex) remain valid — only
+// Molecule-AI/ paths are broken.
+func TestExternalTemplates_NoBrokenMoleculeAIGitHubURLs(t *testing.T) {
+	templates := map[string]string{
+		"externalCurlTemplate":          externalCurlTemplate,
+		"externalChannelTemplate":       externalChannelTemplate,
+		"externalUniversalMcpTemplate":  externalUniversalMcpTemplate,
+		"externalPythonTemplate":        externalPythonTemplate,
+		"externalHermesChannelTemplate": externalHermesChannelTemplate,
+		"externalCodexTemplate":         externalCodexTemplate,
+		"externalOpenClawTemplate":      externalOpenClawTemplate,
+	}
+	// Substrings that imply the snippet is pointing an operator at the
+	// suspended Molecule-AI GitHub org.
+	bannedSubstrings := []string{
+		"github.com/Molecule-AI/",
+		"github.com/molecule-ai/",
+		// Bare `Molecule-AI/<repo>` form used by `/plugin marketplace add`
+		// resolves through GitHub by default — explicit Gitea URL is
+		// required post-suspension.
+		"marketplace add Molecule-AI/",
+		"marketplace add molecule-ai/",
+	}
+	for name, body := range templates {
+		for _, banned := range bannedSubstrings {
+			if strings.Contains(body, banned) {
+				t.Errorf("%s contains %q — Molecule-AI GitHub org is suspended; use git.moleculesai.app/molecule-ai/<repo> instead (RFC #229 P2-5)", name, banned)
+			}
+		}
+	}
+}