fix(account): close deletion cache gap

Require authenticated sidecar cache purge before a deletion can complete and keep failures retryable. Mount tombstones outside restored application data while leaving deletion disabled by default.

tools/summarizer/app.py

@@ -175,6 +175,7 @@ if EAGER_MODEL_LOAD and not SKIP_MODEL_LOAD:
     _ensure_runtime_loaded()
 
 cache = TTLCache(maxsize=1024, ttl=60 * 60)
+cache_lock = threading.Lock()
 
 
 class SummarizeRequest(BaseModel):
@@ -959,8 +960,10 @@ async def summarize(req: SummarizeRequest):
         raise HTTPException(status_code=400, detail="min_length must be smaller than max_length.")
 
     key = _key(req.text, req.max_length, req.min_length, req.top_skills)
-    if key in cache:
-        return {"summary": cache[key], "cached": True}
+    with cache_lock:
+        cached_summary = cache.get(key)
+    if cached_summary is not None:
+        return {"summary": cached_summary, "cached": True}
 
     info = _role_focused_excerpt(req.text)
     summary = _model_summarize(info["focused_input"], req.max_length, req.min_length)
@@ -1028,10 +1031,19 @@ async def summarize(req: SummarizeRequest):
         lines.append("- Prepare examples showing relevant impact, collaboration, and delivery.")
 
     out = "\n".join(lines).strip()
-    cache[key] = out
+    with cache_lock:
+        cache[key] = out
     return {"summary": out, "cached": False}
 
 
+@app.delete("/maintenance/cache")
+async def purge_cache():
+    with cache_lock:
+        cleared = len(cache)
+        cache.clear()
+    return {"cleared": cleared}
+
+
 def _normalize_text(value: str) -> str:
     value = value.replace("\x00", " ")
     return re.sub(r"\s+", " ", value).strip()

tools/summarizer/tests/test_app.py

@@ -510,6 +510,22 @@ def test_health_stays_open_so_probes_and_healthchecks_work(monkeypatch):
     assert client.get("/health").status_code == 200
 
 
+def test_cache_purge_requires_service_token_and_clears_content(monkeypatch):
+    module = load_app_module(monkeypatch, service_token="s3cret")
+    module.cache["synthetic-key"] = "synthetic-summary"
+    client = TestClient(module.app)
+
+    assert client.delete("/maintenance/cache").status_code == 401
+    response = client.delete(
+        "/maintenance/cache",
+        headers={"X-Ai-Service-Token": "s3cret"},
+    )
+
+    assert response.status_code == 200
+    assert response.json() == {"cleared": 1}
+    assert len(module.cache) == 0
+
+
 def test_endpoints_stay_open_when_no_token_is_configured(monkeypatch):
     module = load_app_module(monkeypatch)
     client = TestClient(module.app)