sidecar self-registration: sidecars connect to API server instead of vice versa

Flips the connection model so sidecars register themselves with the API
server via WebSocket at /api/sidecar/register, enabling dynamic discovery,
location independence, and automatic reconnection from either side.

- Add registration protocol types and PTY command/event types
- Create sidecar-registry.ts (replaces sidecar-client.ts) as passive registry
- Create sidecar connector (connect.ts) with exponential backoff reconnect
- Convert process sidecar from WS server to WS client
- Convert PTY sidecar from WS server to multiplexed WS client
- Simplify terminal bridge to thin adapter using registry
- Add PTY sidecar as PM2-managed process
- Update all consumer imports

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

src/servers/channels/discord/handler.ts

@@ -4,7 +4,7 @@ import { sendAndAwait, getSessionModel, setSessionModel } from '../send-and-awai
 import { consumePairingCode } from '../pairing';
 import { chunkMessage } from './chunker';
 import { listPiModels } from '@@/api/pi/list-models';
-import { enqueueJob } from '../../sidecar-client';
+import { enqueueJob } from '../../sidecar-registry';
 import { readJob } from '@@/queue/storage';
 import { openEmailDb } from '@@/api/email/email-db';
 import type { ModelInfo } from '@@/api/pi/types';
@@ -95,9 +95,9 @@ async function handleEmailSync(ctx: CommandContext): Promise<void> {
       return;
     }
 
-    const newest = db.query(
-      'SELECT from_name, from_address, subject FROM emails WHERE deleted = 0 ORDER BY date DESC LIMIT ?',
-    ).all(Math.min(newCount, 20)) as Array<{ from_name: string | null; from_address: string; subject: string }>;
+    const newest = db
+      .query('SELECT from_name, from_address, subject FROM emails WHERE deleted = 0 ORDER BY date DESC LIMIT ?')
+      .all(Math.min(newCount, 20)) as Array<{ from_name: string | null; from_address: string; subject: string }>;
     db.close();
 
     const lines = newest.map((e) => {
@@ -128,9 +128,7 @@ async function handleCommand(ctx: CommandContext): Promise<boolean> {
       '`!model` — show current model\n' +
       '`!model <id>` — switch model\n' +
       '`!models` — list available models',
-    email:
-      '**Email:**\n' +
-      '`!email sync` — sync Gmail and show new emails',
+    email: '**Email:**\n' + '`!email sync` — sync Gmail and show new emails',
   };
 
   if (lower === '!help' || lower.startsWith('!help ')) {
@@ -140,7 +138,11 @@ async function handleCommand(ctx: CommandContext): Promise<boolean> {
       return true;
     }
     if (topic) {
-      await channel.send(`Unknown topic: \`${topic}\`\nAvailable: ${Object.keys(helpSections).map((k) => `\`${k}\``).join(', ')}`);
+      await channel.send(
+        `Unknown topic: \`${topic}\`\nAvailable: ${Object.keys(helpSections)
+          .map((k) => `\`${k}\``)
+          .join(', ')}`,
+      );
       return true;
     }
     const full = Object.values(helpSections).join('\n\n');
@@ -172,7 +174,11 @@ async function handleCommand(ctx: CommandContext): Promise<boolean> {
 
   if (lower === '!model') {
     const current = getSessionModel('discord', ctx.userId, discordId);
-    await channel.send(current ? `Current model: **${current}**` : 'No active session yet — the default model will be used on your next message.');
+    await channel.send(
+      current
+        ? `Current model: **${current}**`
+        : 'No active session yet — the default model will be used on your next message.',
+    );
     return true;
   }
 
@@ -229,17 +235,23 @@ export async function handleDiscordMessage(message: DiscordMessage): Promise<voi
     }
 
     await channel.send(
-      'I don\'t recognize your Discord account. To link it:\n' +
-      '1. Go to Officer Settings → Integrations → Discord\n' +
-      '2. Click "Link Discord" to get a pairing code\n' +
-      '3. Send the 6-character code to me here',
+      "I don't recognize your Discord account. To link it:\n" +
+        '1. Go to Officer Settings → Integrations → Discord\n' +
+        '2. Click "Link Discord" to get a pairing code\n' +
+        '3. Send the 6-character code to me here',
     );
     return;
   }
 
   // Handle commands
   if (content.startsWith('!')) {
-    const handled = await handleCommand({ content, channel, userId: linked.user.id, email: linked.user.email, discordId });
+    const handled = await handleCommand({
+      content,
+      channel,
+      userId: linked.user.id,
+      email: linked.user.email,
+      discordId,
+    });
     if (handled) return;
   }
 

src/servers/channels/send-claude-code.ts

@@ -1,6 +1,6 @@
 import { logger } from '@@/api/pi/logger';
 import type { MessageCost, PiEvent } from '@@/api/pi/types';
-import * as sidecar from '@@/sidecar-client';
+import * as sidecar from '@@/sidecar-registry';
 
 type ClaudeCodeParams = {
   userId: number;

src/servers/channels/telegram/handler.ts

@@ -5,7 +5,7 @@ import { consumePairingCode } from '../pairing';
 import { chunkMessage } from './chunker';
 import { getTelegramBot } from './bot';
 import { listPiModels } from '@@/api/pi/list-models';
-import { enqueueJob } from '../../sidecar-client';
+import { enqueueJob } from '../../sidecar-registry';
 import { readJob } from '@@/queue/storage';
 import { openEmailDb } from '@@/api/email/email-db';
 import type { ModelInfo } from '@@/api/pi/types';

src/servers/channels/whatsapp/handler.ts

@@ -4,7 +4,7 @@ import { sendAndAwait, getSessionModel, setSessionModel } from '../send-and-awai
 import { consumePairingCode } from '../pairing';
 import { getWhatsAppClient } from './bot';
 import { listPiModels } from '@@/api/pi/list-models';
-import { enqueueJob } from '../../sidecar-client';
+import { enqueueJob } from '../../sidecar-registry';
 import { readJob } from '@@/queue/storage';
 import { openEmailDb } from '@@/api/email/email-db';
 import type { ModelInfo } from '@@/api/pi/types';