feat(author-workflow): enforce exact issue lock before branch/commit/push/PR (Issue #204)

Recreation of the #204 work from closed PR #205 (invalid provenance), rebuilt
cleanly on master under the prgs author identity with no PR #203 content:

- Add gitea_lock_issue MCP tool: locks exactly one issue to its branch name,
  fails closed on branch/issue-number mismatch and on issues already tied to
  an open PR (by head branch or Closes/Fixes reference).
- gitea_create_pr now requires the issue lock: head must match the locked
  branch, title/body must contain Closes/Fixes #<locked issue> exactly, and
  ambiguous references (equivalent / related / same as) are rejected.
- scripts/worktree-start refuses to create an issue-linked worktree unless the
  lock file exists and matches the requested branch.
- assess_controller_handoff rejects handoffs whose selected issue / opened PR
  fields carry multiple numbers or fuzzy equivalence wording.
- Tests: TestIssueLocking (lock + create_pr gates), handoff exact-reference
  tests, worktree-start lock coverage.

Closes #204

Co-Authored-By: Claude Fable 5 <[email protected]>

tests/test_worktrees.py

@@ -14,11 +14,39 @@ BRANCHES = REPO / "branches"
 
 
 def run(script, *args):
-    proc = subprocess.run(
-        ["bash", str(SCRIPTS / script), *args],
-        capture_output=True, text=True, cwd=str(REPO),
-    )
-    return proc.returncode, proc.stdout, proc.stderr
+    branch = None
+    for arg in args:
+        if not arg.startswith("-"):
+            branch = arg
+            break
+
+    lock_file = Path("/tmp/gitea_issue_lock.json")
+    created_lock = False
+    if script == "worktree-start" and branch:
+        import re
+        import json
+        m = re.search(r"issue-(\d+)", branch)
+        if not m:
+            m = re.search(r"pr-(\d+)", branch)
+        issue_num = int(m.group(1)) if m else 999
+        lock_file.write_text(json.dumps({
+            "issue_number": issue_num,
+            "branch_name": branch,
+            "remote": "prgs",
+            "org": "Scaled-Tech-Consulting",
+            "repo": "Gitea-Tools"
+        }), encoding="utf-8")
+        created_lock = True
+
+    try:
+        proc = subprocess.run(
+            ["bash", str(SCRIPTS / script), *args],
+            capture_output=True, text=True, cwd=str(REPO),
+        )
+        return proc.returncode, proc.stdout, proc.stderr
+    finally:
+        if created_lock and lock_file.exists():
+            lock_file.unlink()
 
 
 class TestWorktreeStart(unittest.TestCase):