Upgrade to python-mlb-statsapi 1.1.0 and adopt async support

[Mattsface]

Goal

Upgrade python-mlb-statsapi to 1.1.0 and update this app to use its async API where it improves ingestion.

Scope

• Bump dependency to python-mlb-statsapi==1.1.0
• Identify current sync MLB calls used during ingestion
• Convert appropriate ingestion/network paths to async
• Preserve DB-only browser requests
• Keep existing normalization, persistence, and completeness semantics unchanged
• Avoid mixing async network I/O with long-lived database transactions

Tests

• Existing offline suite stays green
• Add focused async-path tests
• Preserve ingestion/idempotence behavior

Out of scope

• UI changes
• Analytics changes
• New MLB data features