chore(githooks): simplify post-receive hook repo root detection

Remove the workaround that derived REPO_TOPLEVEL from
`git rev-parse --absolute-git-dir` and fall back to
`git rev-parse --show-toplevel` directly. Also drop the
related comments and debug echo. The simpler approach is
sufficient for the hook's needs and makes the script easier
to maintain.

.githooks/post-receive

@@ -1,25 +1,14 @@
 #!/bin/sh
 # Post-receive hook: push 后自动 build + start
 #
-# 重要：git 调钩子时 cwd=GIT_DIR（不是工作树根），所以必须先把 cwd
-#       切到工作树根，下面的所有路径（env-example/、logs/、pnpm）才正确。
 
 # pnpm 环境变量
 export NVM_DIR="$HOME/.nvm"
 [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
 [ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion
 
-# 关键：git 调钩子时 cwd=GIT_DIR，且`git rev-parse --show-toplevel`会拒返回。
-# 用 `git rev-parse --absolute-git-dir` 拿到绝对 git-dir 路径，
-# 其父目录就是工作树根。
-GIT_DIR_ABS="$(git rev-parse --absolute-git-dir 2>/dev/null)"
-if [ -n "$GIT_DIR_ABS" ] && [ -d "$GIT_DIR_ABS" ]; then
-    REPO_TOPLEVEL="$(cd "$GIT_DIR_ABS/.." && pwd)"
-else
-    REPO_TOPLEVEL="$(git rev-parse --show-toplevel 2>/dev/null || echo "$PWD")"
-fi
+REPO_TOPLEVEL="$(git rev-parse --show-toplevel 2>/dev/null || echo "$PWD")"
 cd "$REPO_TOPLEVEL" || { echo "FATAL: cannot cd to $REPO_TOPLEVEL" >&2; exit 1; }
-echo "=== REPO_TOPLEVEL=$REPO_TOPLEVEL (GIT_DIR=$GIT_DIR_ABS) ===" >&2
 
 # ============================================================
 # 0. sync_worktree —— 将**工**作**树**同步到**新** push 的 HEAD