fix(githooks): use git rev-parse --absolute-git-dir for repo root

The $0-based dirname trick didn't work because git invokes
hooks with just the basename (e.g., 'post-receive'), not the
absolute path. Use 'git rev-parse --absolute-git-dir' instead,
which works even when CWD is inside .git/.

.githooks/post-receive

@@ -19,21 +19,16 @@
 #   3) **验**证 PATH —— 写日**志**确认 pnpm 可**用**（**不**可用则 build **必**失**败**）
 
 # ---- 前置：切到 repo 顶 + 加 pnpm 到 PATH ----
-# 重要：不能**用** `git rev-parse --show-toplevel` 获**取** repo **顶**层
-# —— git-receive-pack 调 hook 时 CWD **可**能是 `.git/` 内**部**，
-# 这种情况下 `--show-toplevel` **报**错 `must be run in a work tree`。
-# 解**法**：**直**接**根**据 hook **本**身路径推**算** repo **顶**层。
-SCRIPT_DIR="$(cd "$(dirname "$0")" 2>/dev/null && pwd || echo "")"
-if [ -z "$SCRIPT_DIR" ]; then
-    # 兜底：**用** git rev-parse（如**果**可**用**）
-    REPO_TOPLEVEL="$(git rev-parse --show-toplevel 2>/dev/null || true)"
-    if [ -z "$REPO_TOPLEVEL" ]; then
-        # **最**后**兜**底：**直**接**用** PWD
-        REPO_TOPLEVEL="$PWD"
-    fi
+# 重要：git-receive-pack 调 hook 时 CWD **可**能是 `.git/` 内**部**，
+# `git rev-parse --show-toplevel` 会**报**错 `must be run in a work tree`。
+# 解**法**：**用** `git rev-parse --absolute-git-dir` **取**得**绝**对 .git **路**径，
+# 然后 dirname **得**到 repo **顶**层。**这**两个调**用**在 .git/ 内**部**也都**能**成**功**。
+GIT_DIR_ABS="$(git rev-parse --absolute-git-dir 2>/dev/null || true)"
+if [ -n "$GIT_DIR_ABS" ] && [ "$GIT_DIR_ABS" != ".git" ]; then
+    REPO_TOPLEVEL="$(cd "$GIT_DIR_ABS/.." && pwd)"
 else
-    # .githooks/post-receive 的**父**目录**的****父**目录 = repo **顶**
-    REPO_TOPLEVEL="$(cd "$SCRIPT_DIR/.." && pwd)"
+    # 兜底：**用** PWD （**非** bare repo 默**认**钩**子**在 **工**作**树**下）
+    REPO_TOPLEVEL="$PWD"
 fi
 cd "$REPO_TOPLEVEL" || { echo "FATAL: cannot cd to $REPO_TOPLEVEL" >&2; exit 1; }