feat: add Phase F.2 - The Biographer (memory agent)

Add The Biographer household member for user memory management:

Memory Service (direct access layer):
- src/core/memory_service.py for fast, LLM-free lookups
- Profile, preference, and fact management
- Session context with Redis caching
- Steward integration via prefetch_context()

The Biographer Agent:
- src/agents/biographer/ package with PydanticAI agent
- Discreet chronicler personality for privacy
- Tools: recall_semantic, list_memories, store_insight,
  update_profile, update_preference, forget_memory
- Registered with Household Registry on startup

Steward Integration:
- Memory context pre-fetch during analysis
- Profile/preferences included in Butler note
- Keyword-based context determination

Also includes:
- delegate_to_biographer() wrapper
- 34 new tests (capability + memory service)
- Version bump to 1.2.0

Documentation cleanup:
- Removed obsolete PHASE2_COMPLETE.md, PHASE2_PLAN.md
- Removed docs/library-desk-requirements.md
- Moved ORCHESTRATION_SCENARIOS.md to project root

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/agents/biographer/__init__.py

@@ -0,0 +1,34 @@
+"""
+The Biographer - Expert for recording and recalling the user's story.
+
+The Biographer serves as the household's memory keeper, responsible for:
+- Recording and recalling facts about the user's life
+- Storing personal information, preferences, and insights
+- Answering questions like "What car do I drive?", "Where do I work?"
+- Managing what the household knows and remembers
+
+For direct key-based lookups (location, timezone, preferences),
+use the memory_service instead - it's faster and doesn't require LLM.
+The Biographer handles semantic, fuzzy queries.
+"""
+from src.agents.biographer.agent import (
+    get_biographer_agent,
+    run_biographer,
+    run_biographer_stream,
+)
+from src.agents.biographer.capability import (
+    BIOGRAPHER_CAPABILITY,
+    get_biographer_capability,
+    register_biographer,
+    unregister_biographer,
+)
+
+__all__ = [
+    "BIOGRAPHER_CAPABILITY",
+    "get_biographer_capability",
+    "get_biographer_agent",
+    "register_biographer",
+    "unregister_biographer",
+    "run_biographer",
+    "run_biographer_stream",
+]