fix(git): harden Gitea PR metadata lookup

docs/scratchpads/mvp-20260312.md

@@ -653,3 +653,9 @@ Independent security review surfaced three high-impact and four medium findings;
 2. After merge, kickoff M3-01 (DTOs) on `feat/federation-m3-types` with sonnet subagent in worktree
 3. Once M3-01 lands, fan out: M3-02 (harness) || M3-03 (AuthGuard) → M3-04 (ScopeService) || M3-08 (FederationClient)
 4. Re-converge at M3-10 (Integration) → M3-11 (E2E)
+
+### Session 24 — 2026-05-22 — Gitea PR metadata wrapper hardening
+
+- Fixed `packages/mosaic/framework/tools/git/pr-metadata.sh` Gitea path to fail closed on non-2xx API responses instead of normalizing API error JSON into null/empty PR metadata.
+- Added token fallback behavior: try explicit `GITEA_TOKEN`, Mosaic credential-loader token, then matching `~/.git-credentials` HTTPS token; this handles stale host-scoped credential-loader entries while preserving existing credential sources.
+- Confirmed real U-Connect Gitea PRs #1905 and #1908 now return `number`, `headRefName`, `baseRefName`, `state`, `author`, `url`, and `mergeable` correctly, restoring `pr-merge.sh` base branch detection.