fix(notion-search): tighten cache type hints + deterministic TTL=0

Code review polish:
- Type hints: List → List[Dict[str, Any]] for cache_get return and
  cache_put results parameter, since rerank produces dict-shaped entries.
- TTL=0 short-circuits to None deterministically. Previously the test
  for ttl_seconds=0 passed only because clock motion between cache_put
  and cache_get made `time.time() - cached_at > 0` true. Now the
  semantics match the docstring intent.

8/8 tests still pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

custom-skills/31-notion-organizer/code/scripts/_search_cache.py

@@ -6,7 +6,7 @@ import hashlib
 import json
 import time
 from pathlib import Path
-from typing import List, Optional
+from typing import Any, Dict, List, Optional
 
 DEFAULT_CACHE_DIR = Path.home() / ".cache" / "notion-search"
 DEFAULT_TTL_SECONDS = 86400  # 24 hours
@@ -23,11 +23,15 @@ def cache_get(
     *,
     cache_dir: Path = DEFAULT_CACHE_DIR,
     ttl_seconds: int = DEFAULT_TTL_SECONDS,
-) -> Optional[List]:
+) -> Optional[List[Dict[str, Any]]]:
     """Return cached results if file exists and is fresh, else None.
 
     Corrupted cache files are silently treated as misses (and removed).
+    `ttl_seconds <= 0` always returns None (deterministic "always expired").
     """
+    if ttl_seconds <= 0:
+        return None
+
     key = _cache_key(query, candidate_ids)
     path = cache_dir / f"{key}.json"
     if not path.exists():
@@ -52,7 +56,7 @@ def cache_get(
 def cache_put(
     query: str,
     candidate_ids: List[str],
-    results: List,
+    results: List[Dict[str, Any]],
     *,
     cache_dir: Path = DEFAULT_CACHE_DIR,
 ) -> None: