Observability + warming guardrails (Codex)

* client_error details, not just a count: new client_errors table + POST
  /api/client-error (reason/path/user-agent/time) + GET /api/admin/client-errors.
  The boot-seatbelt beacon now sends the reason + path (once per page); the admin
  Overview lists the recent errors so we can tell chunk vs SW vs API vs JS — the
  truth meter for the next day as the new SW propagates.
* Deploy warming now also hits the shell, routes (/play /account /admin), SW,
  version.json, word lists, and icons/logo/font — not just immutable chunks.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

goodnews/queries.py

@@ -567,8 +567,8 @@ def admin_stats(conn: sqlite3.Connection, days: int = 30) -> dict:
         "daily": daily,
         # Boot-failure seatbelt signal — blank-screen risk surfacing.
         "client_errors": {
-            "today": scalar("SELECT COUNT(*) FROM events WHERE kind='client_error' AND day=date('now')"),
-            "window": kc.get("client_error", 0),
+            "today": scalar("SELECT COUNT(*) FROM client_errors WHERE date(created_at)=date('now')"),
+            "window": scalar("SELECT COUNT(*) FROM client_errors WHERE created_at>=date('now',?)", (since,)),
         },
     }