fix: address code review feedback for Phase 1a master
Critical fixes: - C1: Add test for P1a.AC2.3 - newer database version error test now opens in-memory DB, sets schema_version to 999, calls run_migrations, and asserts error containing 'newer version'. Important fixes: - I1: Wrap schema creation in transaction for atomicity using BEGIN IMMEDIATE/COMMIT - I2: Run cargo fmt to fix formatting in 6 files - I3: Fix 3 clippy warnings (redundant closure, collapsible if statements) Minor fixes: - M1: Add path canonicalization in CLI handler for consistent path matching - M2: Update error message to match spec requirements Verification: All 62 tests pass, fmt check passes, 0 clippy warnings Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>