fix: auto-detect issue number in cycle retro from git branch (#495)

## Summary
- `cycle_retro.py` now auto-detects issue number from the git branch name (e.g. `kimi/issue-492` → `492`) when `--issue` is not provided
- `backfill_retro.py` now skips the PR number suffix Gitea appends to titles so it does not confuse PR numbers with issue numbers
- Added tests for both fixes

Fixes #492

Co-authored-by: kimi <kimi@localhost>
Reviewed-on: http://localhost:3000/rockachopa/Timmy-time-dashboard/pulls/495
Co-authored-by: Kimi Agent <kimi@timmy.local>
Co-committed-by: Kimi Agent <kimi@timmy.local>

tests/loop/test_cycle_retro.py

@@ -0,0 +1,86 @@
+"""Tests for scripts/cycle_retro.py issue auto-detection."""
+
+from __future__ import annotations
+
+# Import the module under test — it's a script so we import the helpers directly
+import importlib
+import subprocess
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+SCRIPTS_DIR = Path(__file__).resolve().parent.parent.parent / "scripts"
+
+
+@pytest.fixture(autouse=True)
+def _add_scripts_to_path(monkeypatch):
+    monkeypatch.syspath_prepend(str(SCRIPTS_DIR))
+
+
+@pytest.fixture()
+def mod():
+    """Import cycle_retro as a module."""
+    return importlib.import_module("cycle_retro")
+
+
+class TestDetectIssueFromBranch:
+    def test_kimi_issue_branch(self, mod):
+        with patch.object(subprocess, "check_output", return_value="kimi/issue-492\n"):
+            assert mod.detect_issue_from_branch() == 492
+
+    def test_plain_issue_branch(self, mod):
+        with patch.object(subprocess, "check_output", return_value="issue-123\n"):
+            assert mod.detect_issue_from_branch() == 123
+
+    def test_issue_slash_number(self, mod):
+        with patch.object(subprocess, "check_output", return_value="fix/issue/55\n"):
+            assert mod.detect_issue_from_branch() == 55
+
+    def test_no_issue_in_branch(self, mod):
+        with patch.object(subprocess, "check_output", return_value="main\n"):
+            assert mod.detect_issue_from_branch() is None
+
+    def test_feature_branch(self, mod):
+        with patch.object(subprocess, "check_output", return_value="feature/add-widget\n"):
+            assert mod.detect_issue_from_branch() is None
+
+    def test_git_not_available(self, mod):
+        with patch.object(subprocess, "check_output", side_effect=FileNotFoundError):
+            assert mod.detect_issue_from_branch() is None
+
+    def test_git_fails(self, mod):
+        with patch.object(
+            subprocess,
+            "check_output",
+            side_effect=subprocess.CalledProcessError(1, "git"),
+        ):
+            assert mod.detect_issue_from_branch() is None
+
+
+class TestBackfillExtractIssueNumber:
+    """Tests for backfill_retro.extract_issue_number PR-number filtering."""
+
+    @pytest.fixture()
+    def backfill(self):
+        return importlib.import_module("backfill_retro")
+
+    def test_body_has_issue(self, backfill):
+        assert backfill.extract_issue_number("fix: foo (#491)", "Fixes #490", pr_number=491) == 490
+
+    def test_title_skips_pr_number(self, backfill):
+        assert backfill.extract_issue_number("fix: foo (#491)", "", pr_number=491) is None
+
+    def test_title_with_issue_and_pr(self, backfill):
+        # [loop-cycle-538] refactor: ... (#459) (#481)
+        assert (
+            backfill.extract_issue_number(
+                "[loop-cycle-538] refactor: remove dead airllm (#459) (#481)",
+                "",
+                pr_number=481,
+            )
+            == 459
+        )
+
+    def test_no_pr_number_provided(self, backfill):
+        assert backfill.extract_issue_number("fix: foo (#491)", "") == 491