Complete phase 7 regression test coverage

Add regression tests for content publishing and LLM timeouts

Extend testing roadmap

Add webclient unit tests (Vitest) — 47 tests ...

- Vitest + @vue/test-utils + happy-dom setup
- api/index.test.js: 8 tests for fetch wrapper, verbs, errors, FormData
- stores/chat.test.js: 23 tests for buildMessageList, WS handlers, load/clear
- stores/sessions.test.js: 6 tests for fetch, create, delete, pin, preview
- stores/profiles.test.js: 3 tests for fetch, auto-select, lookup
- composables/useWebSocket.test.js: 7 tests with MockWebSocket
- Export buildMessageList from chat store so tests can verify message parsing
- Update docs/testing.md with webclient stack, layout, and commands

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Add 62 tests across all planned phases + fix integration flakiness ...

- Phase 3: 19 API route integration tests (health, agents, sessions, messages)
- Phase 3: 7 WebSocket integration tests (connect, send, replay, invalid, stop)
- Phase 4: 9 agent tests (_check_context_size, _iter_stream_guarded)
- Phase 4: 5 planning tests (_parse_plan_steps)
- Phase 5: 22 tool tests (filesystem 13, code_exec 5, terminal 4)
- Fix flaky integration tests by patching module-level singletons
  (_session_store, _registries, _workers) instead of getter functions,
  because FastAPI Depends() captures the original function at import time.
- Update docs/testing.md coverage table (150 total tests)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Phase 2 — Memory store + extractor unit tests ...

- tests/conftest_factory.py: add FakeRecord, FakeConnection, FakePool, make_store_with_pool
- tests/unit/memory/test_store.py: 18 tests for upsert, vector/ILIKE search, delete, list, count, summary, session state, backfill
- tests/unit/memory/test_extractor.py: 11 tests for JSON extraction, invalid JSON, empty response, tool result truncation, summary regeneration
- docs/testing.md: update coverage status, add FakePool usage example

88 total tests passing (59 + 29).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Bootstrap test suite — Phase 1 unit tests ...

- docs/testing.md: testing strategy, mock strategy, phase breakdown
- tests/conftest.py: autouse fixture to reset navi.config.settings per test
- tests/conftest_factory.py: FakeLLMBackend, FakeTool, make_profile, make_registry helpers
- tests/unit/core/test_events.py: wire serialization for all 15 event dataclasses
- tests/unit/core/test_compressor.py: should_compress, partition_messages, format_for_summary, compress_context
- tests/unit/core/test_registry.py: ToolRegistry, ProfileRegistry, BackendRegistry
- tests/unit/core/test_context_builder.py: system prompt caching, persona injection, goal anchor, iteration budget
- tests/unit/profiles/test_base.py: Pydantic model coercion, defaults, extra fields
- navi/core/context_builder.py: use module-level `import navi.config` instead of `from navi.config import settings` so tests can swap the singleton

59 tests passing.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>