chore: 移除过时 Python 脚本，密钥生成改用 shell 脚本

- generate_keys.py 替换为 generate_keys.sh (无需 Python 依赖)
- 移除已废弃的 backfill_provider_key_status_snapshot.py

scripts/backfill_provider_key_status_snapshot.py

@@ -1,101 +0,0 @@
-from __future__ import annotations
-
-import argparse
-from typing import Any
-
-from sqlalchemy import select
-from sqlalchemy.orm import joinedload, load_only
-
-from src.database import create_session
-from src.models.database import Provider, ProviderAPIKey
-from src.services.provider_keys.status_snapshot_store import sync_provider_key_status_snapshot
-
-
-def parse_args() -> argparse.Namespace:
-    parser = argparse.ArgumentParser(
-        description="Backfill provider_api_keys.status_snapshot from existing OAuth/account/quota fields."
-    )
-    parser.add_argument(
-        "--batch-size",
-        type=int,
-        default=200,
-        help="Number of provider keys to process per commit.",
-    )
-    parser.add_argument(
-        "--include-existing",
-        action="store_true",
-        help="Recompute rows that already have status_snapshot instead of only filling missing rows.",
-    )
-    return parser.parse_args()
-
-
-def build_batch_stmt(
-    *,
-    batch_size: int,
-    last_id: str | None,
-    include_existing: bool,
-) -> Any:
-    stmt = (
-        select(ProviderAPIKey)
-        .options(joinedload(ProviderAPIKey.provider).load_only(Provider.provider_type))
-        .order_by(ProviderAPIKey.id)
-        .limit(batch_size)
-    )
-    if last_id is not None:
-        stmt = stmt.where(ProviderAPIKey.id > last_id)
-    if not include_existing:
-        stmt = stmt.where(ProviderAPIKey.status_snapshot.is_(None))
-    return stmt
-
-
-def main() -> int:
-    args = parse_args()
-    batch_size = max(1, int(args.batch_size or 200))
-    include_existing = bool(args.include_existing)
-
-    db = create_session()
-    processed = 0
-    updated = 0
-    last_id: str | None = None
-
-    try:
-        while True:
-            batch = (
-                db.execute(
-                    build_batch_stmt(
-                        batch_size=batch_size,
-                        last_id=last_id,
-                        include_existing=include_existing,
-                    )
-                )
-                .scalars()
-                .all()
-            )
-            if not batch:
-                break
-
-            for key in batch:
-                last_id = str(key.id)
-                processed += 1
-                previous = getattr(key, "status_snapshot", None)
-                current = sync_provider_key_status_snapshot(key)
-                if current != previous:
-                    updated += 1
-
-            db.commit()
-            print(
-                f"processed={processed} updated={updated} last_id={last_id}",
-                flush=True,
-            )
-
-        print(
-            f"backfill finished: processed={processed} updated={updated} include_existing={include_existing}",
-            flush=True,
-        )
-        return 0
-    finally:
-        db.close()
-
-
-if __name__ == "__main__":
-    raise SystemExit(main())