infra(ci): apply golangci-lint --no-config fix to staging (mc#1099)

Staging's ci.yml still has `golangci-lint --timeout 3m` without --no-config,
so the 3m ceiling from `.golangci.yaml timeout: 3m` is still active.
Cold Gitea act-runners take ~4-7 minutes for golangci-lint on a fresh
module cache, causing Platform (Go) to fail just under the 20m ceiling.

Changes (mirrors PR #1132 on main):
- --no-config bypasses .golangci.yaml ceiling so --timeout takes effect
- --timeout 3m → 10m (the active constraint instead of 3m config)
- job ceiling 15m → 50m (backstop: 10m lint + 15m diagnostic + 20m test suite on cold runner)
- diagnostic step: if: always() → if: success() (skip on lint fail, avoid double-runtime)
- diagnostic test timeout 60s → 600s

mc#1099

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -147,8 +147,10 @@ jobs:
     continue-on-error: false
     # Job-level ceiling. The go test step below runs with a per-step 10m timeout;
     # this cap catches any step that leaks past that. Set well above 10m so
-    # the per-step timeout is the active constraint.
-    timeout-minutes: 15
+    # the per-step timeout is the active constraint. Raised from 15m to 50m
+    # to account for golangci-lint taking ~10m on cold runners (--no-config)
+    # plus ~25m for diagnostic + test suite on cold runner (mc#1099).
+    timeout-minutes: 50
     defaults:
       run:
         working-directory: workspace-server
@@ -174,14 +176,16 @@ jobs:
         run: go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.12.2
       - if: always()
         name: Run golangci-lint
-        run: $(go env GOPATH)/bin/golangci-lint run --timeout 3m ./...
-      - if: always()
-        name: Diagnostic — per-package verbose 60s
+        # mc#1099: --no-config bypasses .golangci.yaml ceiling; --timeout 10m
+        # is now the active constraint instead of the 3m config ceiling.
+        run: $(go env GOPATH)/bin/golangci-lint run --no-config --timeout 10m ./...
+      - if: success()
+        name: Diagnostic — per-package verbose 600s
         run: |
           set +e
-          go test -race -v -timeout 60s ./internal/handlers/... 2>&1 | tee /tmp/test-handlers.log
+          go test -race -v -timeout 600s ./internal/handlers/... 2>&1 | tee /tmp/test-handlers.log
           handlers_exit=$?
-          go test -race -v -timeout 60s ./internal/pendinguploads/... 2>&1 | tee /tmp/test-pu.log
+          go test -race -v -timeout 600s ./internal/pendinguploads/... 2>&1 | tee /tmp/test-pu.log
           pu_exit=$?
           echo "::group::handlers exit=$handlers_exit (last 100 lines)"
           tail -100 /tmp/test-handlers.log