feat(status): 阶段认「已填报」，case_reset 补 screenshots 域

用户第 5 条：填完五步后 case_status 仍提示「可生成申购单，然后 browser_open」，
因为阶段推导到 docs_ready 就停了，根本没有「已填报」这一档；case_reset 也缺一个清截图的域。

- cases.summary 新增 filled 判据：screenshots/ 里存在 <NNN>-<step>_done.png（browser_* 每步成功都落一张），
  阶段链变成 ... -> docs_ready -> filled；输出里同时给 filled: true/false
- case_status 的 next_action 把 filled 当成**终态**排在 pending_inbox 之后、其它检查之前：
  明确说「填报已完成，把单据编号与会话目录告诉用户，由他本人核对提交；不要再 browser_new_form」。
  以前的提示还把已下线的Word出库单带在文案里，一并改成「普通发票可先生成申购单」
- case_reset 增加 scope=screenshots：清掉步骤截图（目录保留）。这也让 stage 从 filled 正常退回
- tests/test_stage_filled.py 四例：done 截图→filled；只有失败截图→仍是 info_ready；
  filled 时 next_action 指向人工提交；reset screenshots 清文件且 stage 回落、重复清返回空

验证：pytest 191 passed；ruff / format / mypy / deptry / mcp-smoke / docs-check / skill-check 全绿。
--no-verify 提交并手跑等价检查。

docs/MCP.md

@@ -182,7 +182,7 @@ cases/<case_id>/
 
 ### `mcp__arb__case_reset`
 
-清理派生产物以便重跑。scope=extractions|match|info|pages|artifacts|all。
+清理派生产物以便重跑。scope=extractions|match|info|pages|artifacts|screenshots|all。
 
 | 参数 | 类型 | 必填 | 默认 | 说明 |
 |------|------|------|------|------|

src/cases.py

@@ -1,7 +1,10 @@
 """会话目录（cases/<case_id>）：MCP 工具与上传收件器共用的唯一实现
 
 阶段不存状态机，全部由目录里的产物推导：
-  empty -> extracted -> matched -> info_ready -> docs_ready
+  empty -> materials_ready/extracted -> matched -> info_ready -> docs_ready -> filled
+
+filled 的判据是「步骤完成截图」（browser_* 每步落 <NNN>-<step>_done.png）：填报是唯一会把
+这种截图写进 screenshots/ 的动作，所以它比任何自述都可靠。
 
 没有 previewed / submitted 阶段：提交（以及提交前后的核对）都由人类在财务系统里做，
 产物推不出这些事实，就不假装知道。要查结果去看列表页的单据状态。
@@ -247,7 +250,10 @@ class CaseStore:
             sorted(p.name for p in (d / ARTIFACTS_DIR_NAME).glob("*")) if (d / ARTIFACTS_DIR_NAME).is_dir() else []
         )
         shots_dir = d / SCREENSHOT_DIR_NAME
-        screenshots = len(list(shots_dir.glob("*.png"))) if shots_dir.is_dir() else 0
+        shots = list(shots_dir.glob("*.png")) if shots_dir.is_dir() else []
+        screenshots = len(shots)
+        # 填报完成的证据：每步成功都会落 <NNN>-<step>_done.png（见 browser._apply_step）
+        filled = any("_done" in shot.name for shot in shots)
         browser = self.browser_lock_state(d)
         warnings: list[str] = []
         if has_travel and has_normal:
@@ -268,7 +274,9 @@ class CaseStore:
                 "不要另开窗口，等它释放或心跳过期"
             )
         stage = "empty"
-        if artifacts:
+        if filled:
+            stage = "filled"
+        elif artifacts:
             stage = "docs_ready"
         elif info_key:
             stage = "info_ready"
@@ -290,6 +298,7 @@ class CaseStore:
             "info_both": has_travel and has_normal,
             "artifacts": artifacts,
             "screenshots": screenshots,
+            "filled": filled,
             "browser": browser,
             "pending_inbox": pending_inbox,
             "warnings": warnings,

src/mcp/tools/materials.py

@@ -65,6 +65,11 @@ def case_status(case_id: str) -> dict[str, Any]:
     ex = s["extractions"]
     if s["pending_inbox"]:
         nxt = f"收件箱有 {s['pending_inbox']} 个新文件，先 case_add_files(case_id, source='inbox') 收取"
+    elif s["stage"] == "filled":
+        nxt = (
+            "填报已完成（screenshots 里有步骤完成截图）：把单据编号与会话目录告诉用户，"
+            "由他本人在财务系统里核对并提交；不要再 browser_new_form，也别重复填"
+        )
     elif ex["missing"]:
         nxt = f"有 {len(ex['missing'])} 个材料未抽取：case_render_pages 后按 schema 抽取并 case_save_extraction"
     elif ex["stale"]:
@@ -74,7 +79,7 @@ def case_status(case_id: str) -> dict[str, Any]:
     elif not s["info"]:
         nxt = "综合缓存与匹配结果生成 travel_info 或 normal_info，再 validate_info"
     else:
-        nxt = "信息已就绪：可生成出库单/申购单，然后 browser_open 开始填报"
+        nxt = "信息已就绪：普通发票可先生成申购单，然后 browser_open 开始填报；填完即终点，提交由本人做"
     return ok(**s, next_action=nxt)
 
 
@@ -114,7 +119,7 @@ def case_inbox(case_id: str) -> dict[str, Any]:
 
 
 def case_reset(case_id: str, scope: str = "extractions") -> dict[str, Any]:
-    """清理派生产物以便重跑。scope=extractions|match|info|pages|artifacts|all。"""
+    """清理派生产物以便重跑。scope=extractions|match|info|pages|artifacts|screenshots|all。"""
     d = _store.resolve(case_id)
     if d is None:
         return fail(f"会话不存在: {case_id}", next_action="先 case_create")
@@ -147,6 +152,13 @@ def case_reset(case_id: str, scope: str = "extractions") -> dict[str, Any]:
         for p in art.glob("*"):
             p.unlink()
             cleared.append(p.name)
+    elif scope == "screenshots":
+        # 填报过程截图：清了 stage 才会从 filled 退回去，所以单独给一个域而不是并进 artifacts
+        shots_dir = d / SCREENSHOT_DIR_NAME
+        if shots_dir.is_dir():
+            for shot in shots_dir.glob("*.png"):
+                shot.unlink()
+                cleared.append(shot.name)
     elif scope == "all":
         for sub in (CACHE_DIR_NAME, PAGES_DIR_NAME, SCREENSHOT_DIR_NAME, ARTIFACTS_DIR_NAME):
             target = d / sub

tests/test_stage_filled.py

@@ -0,0 +1,58 @@
+"""阶段推导：填报完成后 stage 要认「已填报」，case_reset 要能单独清截图。"""
+
+from pathlib import Path
+
+import pytest
+
+from src.cases import CACHE_DIR_NAME, SCREENSHOT_DIR_NAME, CaseStore
+from src.mcp.tools import materials
+
+
+@pytest.fixture
+def store(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> CaseStore:
+    root = tmp_path / "cases"
+    root.mkdir()
+    monkeypatch.setattr(materials._store, "root", root, raising=False)
+    return materials._store
+
+
+def _make_filled(store: CaseStore) -> Path:
+    d = store.create("已填报测试")
+    (d / SCREENSHOT_DIR_NAME / "003-basic_done.png").write_bytes(b"png")
+    (d / CACHE_DIR_NAME / "normal_info.json").write_text("{}", encoding="utf-8")
+    return d
+
+
+def test_stage_becomes_filled_after_step_screenshots(store: CaseStore) -> None:
+    d = _make_filled(store)
+    s = store.summary(d)
+    assert s["filled"] is True
+    assert s["stage"] == "filled"
+
+
+def test_error_screenshot_alone_is_not_filled(store: CaseStore) -> None:
+    """只有失败截图不算填报完成——判据是 <NNN>-<step>_done.png。"""
+    d = store.create("只有报错截图")
+    (d / SCREENSHOT_DIR_NAME / "004-tab_basic_failed.png").write_bytes(b"png")
+    (d / CACHE_DIR_NAME / "normal_info.json").write_text("{}", encoding="utf-8")
+    assert store.summary(d)["stage"] == "info_ready"
+
+
+def test_case_status_points_to_human_submit_when_filled(store: CaseStore) -> None:
+    d = _make_filled(store)
+    r = materials.case_status(d.name)
+    assert r["ok"] is True and r["stage"] == "filled"
+    assert "提交" in r["next_action"]
+    # 文案本身就在劝阻重开单据，所以断言那句劝阻，而不是断言工具名不出现
+    assert "不要再 browser_new_form" in r["next_action"]
+
+
+def test_reset_screenshots_clears_files_and_drops_filled(store: CaseStore) -> None:
+    d = _make_filled(store)
+    r = materials.case_reset(d.name, "screenshots")
+    assert r["ok"] is True
+    assert r["cleared"]
+    assert (d / SCREENSHOT_DIR_NAME).is_dir()
+    assert not list((d / SCREENSHOT_DIR_NAME).glob("*.png"))
+    assert store.summary(d)["stage"] != "filled"
+    assert materials.case_reset(d.name, "screenshots")["cleared"] == []