fix: resolve all mypy type errors for strict type checking (#48)

## Summary

Fixed 30 mypy type errors across 8 files to enable strict type checking.

## Changes by Category

### no-any-return errors (fixed with explicit type casts)
- alerter/history.py: Cast Redis zcount/zremrangebyscore returns to int
- ingestor/clob_client.py: Cast API response values appropriately
- ingestor/publisher.py: Cast Redis xack, xlen, xtrim returns to int
- ingestor/metadata_sync.py: Cast Redis delete return to int
- detector/scorer.py: Cast Redis delete return to int

### operator errors (fixed with null checks)
- alerter/formatter.py: Added `if age_hours is not None:` guards

### External library typing issues (fixed with type: ignore)
- ingestor/publisher.py: redis-py typing issue with xadd dict parameter
- profiler/funding.py: web3 typing issue with block parameters
- storage/repos.py: SQLAlchemy Result.rowcount typing issue

### assignment errors (fixed by renaming)
- storage/repos.py: Renamed SQLite insert stmt to avoid type conflict

Closes #48

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/polymarket_insider_tracker/detector/scorer.py

@@ -268,7 +268,7 @@ class RiskScorer:
         """
         key = f"{self._key_prefix}{wallet_address}:{market_id}"
         deleted = await self._redis.delete(key)
-        return deleted > 0
+        return int(deleted) > 0
 
     async def assess_batch(self, bundles: list[SignalBundle]) -> list[RiskAssessment]:
         """Assess multiple trade bundles.