fix(githooks): cd to repo top + load pnpm into PATH

- cd to repo toplevel first (defensive: git-receive-pack CWD may differ)
- source nvm or directly find pnpm binary if not in PATH
- prepend pnpm's dir to PATH so build/start work

Root cause: post-receive hook was not being triggered on push.
With core.hooksPath=.githooks (relative), git-receive-pack
resolved the path incorrectly. Also pnpm wasn't in PATH during
non-interactive shell invocation.

.githooks/post-receive

@@ -1,7 +1,4 @@
 #!/bin/sh
-
-# MARKER
-touch /tmp/.hook-marker
 # Post-receive hook: push 后自动 build + start
 #
 # 触发场景：
@@ -15,6 +12,37 @@ touch /tmp/.hook-marker
 #   - **全**局变量：LOG_FILE（在 init_log_file **里**定**义**）、CURRENT_BRANCH
 #   - **函**数**间**通过 `$LOG_FILE` / `$BUILD_EXIT` 通信
 #   - **不**用 set -e —— 各步**自**己处理错**误**（env 不**存**在 / build 失败 / 旧**进**程**不**存**在）→ 让 deploy 错**误****不**挡 git push
+#
+# 关键前置（**解**决 push 后 hook **不**触**发** + pnpm **找**不**到**）：
+#   1) cd 到 repo **顶**层 —— git-receive-pack 调 hook 时 CWD **未**必 = repo 顶
+#   2) 加**载** nvm —— 非交互 shell **不**会 source .bashrc，pnpm **不**在 PATH
+#   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 ----
+REPO_TOPLEVEL="$(git rev-parse --show-toplevel)"
+cd "$REPO_TOPLEVEL" || { echo "FATAL: cannot cd to $REPO_TOPLEVEL" >&2; exit 1; }
+
+# 加**载** nvm（**非**交互 shell **不**自动 source .bashrc）
+# nvm 是 POSIX **兼**容，但**有**个**问**题：它**会** [ -n "$BASH_VERSION" ] **检**查，
+# 在 dash **下** nvm 函**数**注**册**失败（pnpm **仍**然**找**不**到**）。
+# 所以策略是：尝**试** source nvm，**如**果失**败**则**直**接**找** pnpm **可执**行文件路径。
+PNPM_BIN="$(command -v pnpm 2>/dev/null || true)"
+if [ -z "$PNPM_BIN" ] && [ -s "$HOME/.nvm/nvm.sh" ]; then
+    \. "$HOME/.nvm/nvm.sh" 2>/dev/null || true
+    PNPM_BIN="$(command -v pnpm 2>/dev/null || true)"
+fi
+# 兜底：**直**接**搜**索 **常**见 nvm 路**径**
+if [ -z "$PNPM_BIN" ]; then
+    for candidate in /root/.nvm/versions/node/*/bin/pnpm "$HOME/.local/share/pnpm/pnpm" /usr/local/bin/pnpm; do
+        if [ -x "$candidate" ]; then
+            PNPM_BIN="$candidate"
+            break
+        fi
+    done
+fi
+if [ -n "$PNPM_BIN" ]; then
+    export PATH="$(dirname "$PNPM_BIN"):$PATH"
+fi
 
 # ============================================================
 # 1. init_log_file —— 定**义** LOG_FILE + 创**建** logs/ 目**录**