Create Comprehensive Test Suite

[tldrwtf]

Description

Create comprehensive test suite with 70%+ coverage. BLOCKS PRODUCTION CUTOVER.

Tasks

• Unit tests for utilities (Logger, TimeUtils, SteamUtils, SpamFilter)
• Unit tests for validators and trading logic
• Unit tests for command classes
• Integration tests for handlers (with mocked Steam clients)
• Integration tests for trading flows
• Set up Jest configuration
• Achieve 70%+ code coverage
• Create .github/workflows/test.yml for CI

Files to Create

• src/**/*.test.ts (20+ test files)
• .github/workflows/test.yml

Dependencies

All implementation complete (Phases 1-5)

Priority

P0 - Critical path

Size

XL (16+ hours)

Critical Note

BLOCKS Issues #41, #42, #43 - Cutover cannot proceed until test suite passes with 70%+ coverage.

Phase

Phase 6 - Integration & Cutover

Parent Issue

#12