v5.3

v5.3 Coverage Expansion to 80% Targets

Delivered: Coverage expansion with quality gates, edge case testing, and integration workflows across all platforms

Key accomplishments:
- Progressive coverage enforcement (70% → 75% → 80%) with emergency bypass
- Coverage trend monitoring with PR comments and assert-to-test ratio tracking
- Quick wins: 80%+ coverage for DTOs, utilities, UI components across platforms
- Core services coverage: governance (64%), canvas (38%), HTTP (96%), LLM (36.5%), episodic (21%)
- Edge case and integration testing: 280 tests for error boundaries, routing, accessibility (WCAG 2.1 AA), concurrent operations, E2E workflows

See .planning/MILESTONES.md for full details.