process sidecar: independent process manager for long-running work

Introduces a separate Bun process (port 5100) that owns all spawned
processes and long-running work, so the API server can restart freely
without disrupting active sessions.

The sidecar owns:
- Anthropic proxy (port 5051) with persisted secret across restarts
- Claude Code process spawning and session tracking (--resume support)
- Pi agent spawning and RPC lifecycle (prompt/abort/thinking)
- Job queue engine (lane processing, retries, notifications)

The API server becomes a thin client that forwards commands over a
single WebSocket connection with auto-reconnect. send-claude-code.ts
goes from 550 lines of spawn logic to 73 lines of sidecar delegation.

State persisted to data/sidecar/state.json every 30s and on shutdown.
Lockfile prevents duplicate instances. See SIDECAR.md for full docs
and manual testing procedures.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/servers/bootstrap.ts

@@ -8,7 +8,7 @@ import { syncSeedExtensions } from './sync-extensions';
 import { syncSeedResources } from './sync-resources';
 import { migrateSettingsToResources } from './migrate-resources';
 import { generateResourceSkill } from './api/pi/pi-bridge';
-import { initQueue } from './queue';
+// Queue is now owned by the sidecar process
 import { startDiscordBotIfConfigured } from './channels/discord/bot';
 import { startTelegramBotIfConfigured } from './channels/telegram/bot';
 import { startWhatsAppBotIfConfigured } from './channels/whatsapp/bot';
@@ -78,9 +78,7 @@ async function installPi(): Promise<boolean> {
   await migrateSettingsToResources();
   generateResourceSkill(DATA_PATH);
 
-  await initQueue().catch((err) => {
-    console.error('[bootstrap] Failed to initialize queue:', err);
-  });
+  // Queue is initialized by the sidecar process
 
   await startDiscordBotIfConfigured().catch((err) => {
     console.error('[channels] Failed to start Discord bot:', err);