fix(tests): auto-init submodules when bats binary is missing

Fresh worktrees don't have submodules checked out, so the pre-push
run-tests hook failed on first push with a manual-fix error message.
run-bats.sh now runs `git submodule update --init --recursive`
automatically instead of just printing instructions.

Also records two lessons from working across bare-repo/worktree
boundaries this session: the repo root has no working tree (edits
there are invisible to git), and local remote-tracking refs go stale
after a merge — verify via the Gitea API before asking about cleanup.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FNJWdVvdgvZCHi1hZGqgVQ

tests/run-bats.sh

@@ -7,8 +7,12 @@ REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 BATS="$REPO_ROOT/tests/bats/bin/bats"
 
 if [[ ! -x "$BATS" ]]; then
-    echo "Error: bats not found at $BATS" >&2
-    echo "       Run: git submodule update --init --recursive" >&2
+    echo "bats not found at $BATS — initializing submodules..." >&2
+    git -C "$REPO_ROOT" submodule update --init --recursive
+fi
+
+if [[ ! -x "$BATS" ]]; then
+    echo "Error: bats still not found at $BATS after submodule init" >&2
     exit 1
 fi