feat: wire up all Phase 2-6 features into daemon and config

Integrate all new features into the shared infrastructure:
- Config schema: add memory, discord, slack, process, web_search schemas
- Daemon wiring: memory store init, tool registration, channel adapters
- Orchestrator: memory injection into system prompt, extraction on compaction
- Agent: add setSystemPrompt() for dynamic prompt updates
- Channel/tool index: export new adapters and tool factories
- Add @slack/bolt, discord.js, turndown, linkedom, @mozilla/readability deps
- Update state.json with Phase 3b completion (494 tests passing)

AGENTS.md

@@ -1,5 +1,9 @@
 # Flynn AGENTS.md
 
+## General Rules
+
+- **Parallelise with subagents:** For every task, use multiple subagents with the appropriate model to work more efficiently. Dispatch independent subtasks in parallel rather than executing them sequentially.
+
 ## Build, Lint, and Test Commands
 
 ```bash