Consolidate shared helpers (format_rating, format_swar, tier_style,
format_relative_time) into widgets/mod.rs and screens/mod.rs. Replace
heap allocations with stack arrays and HashSets, parallelize DB queries
with tokio::try_join, wrap schema init in transactions, use OnceLock for
invariant hashes, and fix clippy warnings. Auto-sync on dashboard mount
when last sync >24h ago. All 105 tests pass.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>