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)

src/channels/index.ts

@@ -9,3 +9,5 @@ export type {
 export { ChannelRegistry } from './registry.js';
 export { TelegramAdapter, type TelegramAdapterConfig } from './telegram/index.js';
 export { WebChatAdapter, type WebChatAdapterConfig } from './webchat/index.js';
+export { DiscordAdapter, type DiscordAdapterConfig } from './discord/index.js';
+export { SlackAdapter, type SlackAdapterConfig } from './slack/index.js';