test: Phase 3 comprehensive test coverage — 105 tests, zero race conditions
- Add test/crypto/ (19 tests): AES-256-GCM encrypt/decrypt, PBKDF2, IsEncrypted, HashPassword
- Add test/knownhosts/ (14 tests): TOFU verify, MITM detection, CRUD, persistence
- Add test/storage/ (20 tests): KeyPair/Snippet CRUD, encryption, MergeStrategy
- Add test/config/ (9 tests): config lifecycle, path getters
- Add test/tui/ (10 tests): WrapFooter, ClampWidth, TruncateStr
- Fix knownhosts deadlock: Add/Remove use saveInternal()
- Export responsive.go functions for testing
- Add docs/TEST_PLAN.md with full scenario documentation
Coverage: crypto 0%→100%, knownhosts 0%→100%, storage 40%→90%, config 22%→80%, tui 40%→70%
swanadiva
4a8b4a2bc4