ci: mypy ratchet -- keep type-clean modules clean (71 modules, 536 -> 442 errors) (#661)

* ci: mypy ratchet -- keep type-clean modules clean

mypy-clean.txt lists the 71 modules under src/ that type-check clean;
scripts/check_types.py runs mypy (--follow-imports=silent) on exactly
those files and fails on any error or a missing/unsorted/duplicate entry.
A new "Type check (mypy ratchet)" CI job runs it with mypy 1.20.2 and
pinned stubs; the manual pre-commit mypy hook now runs the same script
(a local hook, so mypy sees the installed requirements like CI does).

35 modules were made clean with annotation-only fixes: hints, typing.cast,
TYPE_CHECKING imports, implicit-Optional defaults made explicit, and
annotations widened (never guards removed) where mypy called a defensive
isinstance check unreachable. No runtime behaviour change.

mypy.ini: numpy and orjson are treated as Any (follow_imports=skip, also
for stubs). numpy 2.3+ stubs use 3.12 `type` statements that mypy won't
parse at python_version 3.10, and orjson is optional, so seeing its stubs
made the result depend on whether it was installed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* chore: annotate check_types.py's list-form mypy subprocess

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

src/common/espn_dates.py

@@ -37,7 +37,7 @@ import time
 from concurrent.futures import ThreadPoolExecutor
 from datetime import date, timedelta
 from functools import partial
-from typing import Any, Dict, List, Optional, Tuple
+from typing import Any, Dict, List, Optional, Tuple, cast
 
 try:
     from src.common.json_body import response_json
@@ -159,7 +159,7 @@ def espn_date_chunks(start: date, end: date) -> List[str]:
     return chunks
 
 
-def merge_scoreboard_payloads(payloads: List[Dict[str, Any]]) -> Dict[str, Any]:
+def merge_scoreboard_payloads(payloads: List[Any]) -> Dict[str, Any]:
     """Fold chunk responses into one scoreboard payload.
 
     Events are de-duplicated by id and keep first-seen order. Non-event keys
@@ -202,7 +202,7 @@ def _fetch_one_chunk(
             timeout=timeout,
         )
         response.raise_for_status()
-        return response_json(response)
+        return cast(Optional[Dict[str, Any]], response_json(response))
     except Exception as exc:  # noqa: BLE001 - see docstring
         if logger:
             logger.warning("ESPN chunk %s failed, skipping it: %s", chunk, exc)
@@ -379,4 +379,4 @@ def fetch_espn_scoreboard(
         if data is not None:
             return data
     response.raise_for_status()
-    return response_json(response)
+    return cast(Dict[str, Any], response_json(response))