feat: backend gate fallback + metric_diff docs + submit_sft fix

- Auto-inject human-review gate when agent asks question but forgets gate entry
- Add complex_dev/complex_base field docs to program.md metric_diff table
- Fix submit_sft.sh minor issues
- jupyter_runtime improvements

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/api/server.py

@@ -2031,6 +2031,9 @@ def create_app(state: AgentState) -> FastAPI:
             session_id,
         )
         run_active = _is_run_active(state, account_id, session_id)
+        state_entries = _maybe_inject_gate_fallback(
+            state_path, state_entries, sessions_dir, session_id, run_active,
+        )
         _apply_program_state(
             payload,
             state_entries,
@@ -2104,6 +2107,9 @@ def create_app(state: AgentState) -> FastAPI:
                         session_id,
                     )
                     run_active = _is_run_active(state, account_id, session_id)
+                    state_entries = _maybe_inject_gate_fallback(
+                        state_path, state_entries, sessions_dir, session_id, run_active,
+                    )
                     _apply_program_state(
                         payload,
                         state_entries,
@@ -6606,6 +6612,85 @@ def _compute_in_flight(
     }
 
 
+_QUESTION_PATTERN = re.compile(
+    r'[？?]|拍板|选择.*哪|决定|确认.*吗|建议.*哪|要不要|是否|请.*选|你.*决定|三个选项|哪个方案|哪条路'
+)
+
+
+def _last_assistant_text(sessions_dir: Path, session_id: str | None) -> str | None:
+    if not session_id:
+        return None
+    safe_id = _safe_session_id(session_id)
+    if safe_id is None:
+        return None
+    path = sessions_dir / safe_id / 'session.json'
+    try:
+        data = json.loads(path.read_text(encoding='utf-8'))
+    except (OSError, json.JSONDecodeError):
+        return None
+    messages = data.get('messages')
+    if not isinstance(messages, list):
+        return None
+    for msg in reversed(messages):
+        if not isinstance(msg, dict):
+            continue
+        if msg.get('role') != 'assistant':
+            continue
+        content = msg.get('content')
+        if isinstance(content, str) and content.strip():
+            return content.strip()
+        if isinstance(content, list):
+            for block in content:
+                if isinstance(block, dict) and block.get('type') == 'text':
+                    text = block.get('text', '').strip()
+                    if text:
+                        return text
+    return None
+
+
+def _maybe_inject_gate_fallback(
+    state_path: Path,
+    state_entries: list[dict[str, Any]],
+    sessions_dir: Path,
+    session_id: str | None,
+    run_active: bool | None,
+) -> list[dict[str, Any]]:
+    """If agent's last message asks a question but no gate is running,
+    append a synthetic human-review entry to program-state.jsonl."""
+    if run_active is not False:
+        return state_entries
+    for entry in reversed(state_entries):
+        step = entry.get('step')
+        if step in ('human-check', 'human-review') and entry.get('status') == 'running':
+            return state_entries
+    last_text = _last_assistant_text(sessions_dir, session_id)
+    if not last_text:
+        return state_entries
+    if not _QUESTION_PATTERN.search(last_text[-500:]):
+        return state_entries
+    run_id = None
+    for entry in reversed(state_entries):
+        rid = entry.get('run_id')
+        if isinstance(rid, str) and rid.strip():
+            run_id = rid.strip()
+            break
+    gate_entry: dict[str, Any] = {
+        'step': 'human-review',
+        'status': 'running',
+        'run_id': run_id or 'R0',
+        'reason': last_text[-300:],
+        'ts': datetime_utc_iso(),
+        '_synthetic': True,
+    }
+    try:
+        with open(state_path, 'a', encoding='utf-8') as f:
+            f.write(json.dumps(gate_entry, ensure_ascii=False) + '\n')
+    except OSError:
+        pass
+    state_entries.append(gate_entry)
+    return state_entries
+
+
 def _apply_program_state(
     payload: dict[str, Any],
     state_entries: list[dict[str, Any]],