pr: commit worktree changes before push; fix merge/pr order docs

POST /tasks/{id}/pr used to push the branch as-is, so uncommitted
worktree changes never reached the PR (empty diff). Now, after all
skip checks pass, the endpoint commits the worktree on host/<task>
(guarded: refuses when the worktree is on another branch), cleans
__pycache__/*.pyc like host.py merge does, and falls back to the
cloud identity when no git identity is configured. Nothing-to-commit
proceeds. Docs corrected: PR comes after status-merge and before
any local git merge (which deletes branch+worktree).

cloud/pr.py

@@ -13,9 +13,23 @@ host/<host 任务名>，worktree 在 <仓库根>/work/host-worktrees/
   4. 本机没有 gh 二进制 -> pr_skipped, no_gh
   5. gh 未登录（gh auth status 非零） -> pr_skipped,
      gh_not_authenticated
-  只有以上全过才 push 分支 + gh pr create；push 或 pr create
-  失败时抛 PrStepError（调用方据此返回 502），任务状态保持
-  merged 不变，绝不把任务标 failed。
+  只有以上全过才提交 worktree 改动、push 分支 + gh pr create；
+  push 或 pr create 失败时抛 PrStepError（调用方据此返回 502），
+  任务状态保持 merged 不变，绝不把任务标 failed。
+
+  提交规则（create_task_pr 在全部跳过检查通过后、push 之前做）：
+  worktree 必须正好在分支 host/<任务名> 上，否则直接失败，
+  绝不在别的分支上提交；先清掉 worktree 内的 __pycache__ /
+  *.pyc（与 host.py merge 同规则，只动 worktree，不动主仓），
+  再 git add -A + commit；nothing to commit 时直接继续。
+  身份用环境里的 git 身份（与 host.py merge 一致），缺身份时
+  回退到 cloud/cloud@local 再试一次。
+
+  顺序约束（与云端 merge 接口配套）：任务 completed -> 调
+  POST /tasks/{id}/merge 改状态 -> 调 POST /tasks/{id}/pr 推分支
+  建 PR -> 再在 GitHub 上合 PR 或本地 host.py merge。本地
+  host.py merge 成功后会删分支和 worktree，此后调 PR 会跳过
+  no_worktree，所以 PR 必须在本地 git merge 之前做。
 
   worker 不自动推：自动 PR 只由显式调 POST /tasks/{id}/pr
   触发。默认自动推会把测试任务也推到远端，本模块不做。
@@ -118,6 +132,68 @@ def check_pr_ready(worktree_dir, git_runner=None, gh_which=None,
     return True
 
 
+def _commit_worktree_changes(worktree_dir, branch, task_id,
+                             git_runner=None):
+    """push 之前把 worktree 的改动提交到分支上。
+
+    顺序：先确认 worktree 正好在目标分支上（不在就直接失败，
+    绝不在别的分支上提交，commit 到 main 里就污染主分支了）；
+    再清掉 worktree 内的 __pycache__ / *.pyc（可再生的缓存，
+    与 host.py merge 同规则）；再 git add -A + commit。
+    nothing to commit 时直接返回；缺 git 身份时回退到
+    cloud/cloud@local 再试一次；其它失败抛 PrStepError(commit)。
+    """
+    cur = _run(["git", "-C", worktree_dir, "branch", "--show-current"],
+               cwd=worktree_dir, runner=git_runner)
+    if (getattr(cur, "stdout", "") or "").strip() != branch:
+        raise PrStepError(
+            "commit", "worktree 不在分支 %s 上，拒绝提交" % branch)
+    for root, dirs, files in os.walk(worktree_dir):
+        if ".git" in dirs:
+            dirs.remove(".git")
+        if "__pycache__" in dirs:
+            shutil.rmtree(os.path.join(root, "__pycache__"),
+                          ignore_errors=True)
+            dirs.remove("__pycache__")
+        for fn in files:
+            if fn.endswith(".pyc"):
+                try:
+                    os.remove(os.path.join(root, fn))
+                except OSError:
+                    pass
+    add = _run(["git", "-C", worktree_dir, "add", "-A"],
+               cwd=worktree_dir, runner=git_runner)
+    if getattr(add, "returncode", 1) != 0:
+        raise PrStepError(
+            "commit", "git add 失败：%s" % (
+                (getattr(add, "stderr", "") or "")
+                or (getattr(add, "stdout", "") or "")))
+    msg = "cloud: %s" % task_id
+    c = _run(["git", "-C", worktree_dir, "commit", "-m", msg],
+             cwd=worktree_dir, runner=git_runner)
+    if getattr(c, "returncode", 1) == 0:
+        return
+    out = ((getattr(c, "stdout", "") or "")
+           + (getattr(c, "stderr", "") or ""))
+    if "nothing to commit" in out:
+        return
+    if ("tell me who you are" in out or "user.name" in out
+            or "user.email" in out):
+        c2 = _run(["git", "-C", worktree_dir,
+                   "-c", "user.name=cloud", "-c", "user.email=cloud@local",
+                   "commit", "-m", msg],
+                  cwd=worktree_dir, runner=git_runner)
+        if getattr(c2, "returncode", 1) == 0:
+            return
+        out2 = ((getattr(c2, "stdout", "") or "")
+                + (getattr(c2, "stderr", "") or ""))
+        if "nothing to commit" in out2:
+            return
+        raise PrStepError(
+            "commit", "git commit 失败（已试 cloud 身份）：%s" % out2[:300])
+    raise PrStepError("commit", "git commit 失败：%s" % out[:300])
+
+
 def create_task_pr(task_id, auto_pr, worktrees_root=None,
                    git_runner=None, gh_runner=None, gh_which=None):
     """给一个已 merged 的云端任务建 PR。
@@ -125,6 +201,8 @@ def create_task_pr(task_id, auto_pr, worktrees_root=None,
     auto_pr 不为 1 时直接抛 PrSkipped(auto_pr_disabled)，调用方
     在查 worktree 之前就应先查项目 auto_pr——本函数也再查一次，
     防止直接调用者漏查。成功返回 {pr_url, pr_number, branch}。
+    全部跳过检查通过后，先把 worktree 改动提交到分支再 push，
+    否则未提交的改动进不了 PR。
     """
     if auto_pr != 1:
         raise PrSkipped(_SKIP_AUTO_PR)
@@ -134,6 +212,8 @@ def create_task_pr(task_id, auto_pr, worktrees_root=None,
     branch = "host/" + host_name
     check_pr_ready(worktree_dir, git_runner=git_runner,
                    gh_which=gh_which, gh_runner=gh_runner)
+    _commit_worktree_changes(worktree_dir, branch, task_id,
+                             git_runner=git_runner)
     push = _run(["git", "-C", worktree_dir, "push", "origin", branch],
                 cwd=worktree_dir, runner=git_runner)
     if getattr(push, "returncode", 1) != 0: