Add sub-agent orchestration, MCP tools, and critical bug fixes

Major Features:
- Sub-agent orchestration system with dynamic specialist spawning
  * spawn_sub_agent(): Create specialists with custom prompts
  * delegate(): Convenience method for task delegation
  * Cached specialists for reuse
  * Separate conversation histories and focused context

- MCP (Model Context Protocol) tool integration
  * Zettelkasten: fleeting_note, daily_note, permanent_note, literature_note
  * Search: search_vault (hybrid search), search_by_tags
  * Web: web_fetch for real-time data
  * Zero-cost file/system operations on Pro subscription

Critical Bug Fixes:
- Fixed max tool iterations (15 → 30, configurable)
- Fixed max_tokens error in Agent SDK query() call
- Fixed MCP tool routing in execute_tool()
  * Routes zettelkasten + web tools to async handlers
  * Prevents "Unknown tool" errors

Documentation:
- SUB_AGENTS.md: Complete guide to sub-agent system
- MCP_MIGRATION.md: Agent SDK migration details
- SOUL.example.md: Sanitized bot identity template
- scheduled_tasks.example.yaml: Sanitized task config template

Security:
- Added obsidian vault to .gitignore
- Protected SOUL.md and MEMORY.md (personal configs)
- Sanitized example configs with placeholders

Dependencies:
- Added beautifulsoup4, httpx, lxml for web scraping
- Updated requirements.txt

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

.gitignore

@@ -49,6 +49,9 @@ memory_workspace/memory/*.md
 memory_workspace/memory_index.db
 memory_workspace/users/*.md  # User profiles (jordan.md, etc.)
 memory_workspace/vectors.usearch
+memory_workspace/obsidian/  # Zettelkasten vault (personal notes)
+memory_workspace/SOUL.md  # Personal config (use SOUL.example.md)
+memory_workspace/MEMORY.md  # Personal memory (use MEMORY.example.md)
 
 # User profiles (personal info)
 users/