fix(issue-21): review ec50fbe7 R6 - the unpushed check covers HEAD and every local ref (tags included, stash excluded) in both submodule checks

Both unpushed checks in lib_py/worktree.py - `submodule foreach` over the
initialised checkouts and the direct `--git-dir` walk over the repositories
under the worktree's modules/ - used `HEAD --branches --not --remotes`. A
commit made on a submodule's detached HEAD and kept only by a tag is reachable
from neither, the top-level status stays clean, and worktree_remove.sh then
deleted the repository with its single --force (exit 0).

Both checks now share one rev list, UNPUSHED_REVS = HEAD --exclude=refs/stash
--all --not --remotes: HEAD and every local ref (branches, tags, notes, ...)
minus remote-tracking refs. refs/stash stays out of it because the stash check
(stash list / reflog) owns it, so a stash is reported once, as 'stashes'. As
intended, a local-only note is now protected too. The stash, error, partial
repository and dirty checks are unchanged.

Tests W6l (tag-only commit; initialised submodule and deinit'd repository) and
W6m (annotated tag). The helper header, the stop SKILL.md and the design doc
state the wider rule.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017R3Eg7MEpSWnm1oB9ZPP6G

.agents/skills/lib_py/worktree.py

@@ -24,6 +24,10 @@ import sys
 from typing import Dict, Iterable, List, Optional
 
 OPEN_STATUSES = ("pending", "running")
+# The commits a forced removal would lose (review R6): reachable from HEAD or
+# from any local ref - branches, tags, notes, ... - except refs/stash (the
+# stash check covers it, reflog included), and from no remote-tracking ref.
+UNPUSHED_REVS = ("HEAD", "--exclude=refs/stash", "--all", "--not", "--remotes")
 
 
 def _git(cwd: str, *args: str) -> subprocess.CompletedProcess:
@@ -146,10 +150,12 @@ def submodule_findings(wt: str) -> Dict[str, object]:
     """trace: the worktree git dir holds modules/ (git then refuses a plain
     `worktree remove`, even after a failed init); dirty / unpushed / stashes:
     what a forced removal would destroy - it deletes the worktree's own
-    submodule repositories. `HEAD` is part of the unpushed check: a submodule
-    is on a detached HEAD after `submodule update`, so commits made there are
-    on no branch and `--branches --not --remotes` alone misses them. Stashes
-    live in refs/stash (and its reflog), reachable from neither."""
+    submodule repositories. The unpushed check covers HEAD and every local
+    ref except refs/stash (UNPUSHED_REVS): a submodule is on a detached HEAD
+    after `submodule update`, so its commits may be on no branch, and a commit
+    kept only by a tag (review R6) or a note is lost with the repository just
+    the same. Stashes live in refs/stash and its reflog; the stash check owns
+    them."""
     gd = _git(wt, "rev-parse", "--absolute-git-dir")
     if gd.returncode != 0 or not gd.stdout.strip():
         return {"trace": False, "dirty": "", "unpushed": "", "stashes": "",
@@ -159,7 +165,7 @@ def submodule_findings(wt: str) -> Dict[str, object]:
     if not res["trace"]:
         return res
     checks = (("dirty", "git status --porcelain"),
-              ("unpushed", "git log --oneline HEAD --branches --not --remotes"),
+              ("unpushed", "git log --oneline " + " ".join(UNPUSHED_REVS)),
               ("stashes", "git stash list"))
     errors = []
     for key, cmd in checks:
@@ -177,7 +183,7 @@ def submodule_findings(wt: str) -> Dict[str, object]:
     extra: Dict[str, List[str]] = {"unpushed": [], "stashes": []}
     for d in repos:
         git = ["git", "--git-dir", d, "--work-tree", d]
-        u = subprocess.run(git + ["log", "--oneline", "HEAD", "--branches", "--not", "--remotes"],
+        u = subprocess.run(git + ["log", "--oneline", *UNPUSHED_REVS],
                            capture_output=True, text=True)
         if u.returncode != 0:
             errors.append(f"{d}: cannot list its unpushed commits ({u.stderr.strip() or u.returncode})")