feat(agiliton-account): Phase 1 service scaffold

TypeScript + Fastify service implementing:
- Google + Microsoft SSO (POST /v1/auth/sso/{google,microsoft})
- JWT issuance + LiteLLM virtual key provisioning on first login
- AES-256-GCM encrypted virtual key storage in Postgres
- Conversation CRUD (GET/POST/DELETE /v1/conversations, /messages)
- GDPR export + soft-delete (/v1/me/export, /v1/me/delete)
- WebSocket MCP bridge (/v1/mcp-bridge) with JWT auth
- MCP demux endpoint (/mcp/demux/:customer_id/mcp) for LiteLLM tool routing
- DB migration script creating sb_customers, sb_conversations, sb_messages
- 9 unit tests (bridge + crypto), all passing
- Dockerfile + docker-compose targeting port 4100

CF-3032

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

src/db/pool.ts

@@ -0,0 +1,24 @@
+import { Pool } from "pg";
+import { config } from "../config.js";
+
+export const pool = new Pool({ connectionString: config.dbUrl });
+
+pool.on("error", (err) => {
+  console.error("[db] unexpected pool error", err);
+});
+
+export async function query<T extends object = Record<string, unknown>>(
+  sql: string,
+  params?: unknown[]
+): Promise<T[]> {
+  const { rows } = await pool.query<T>(sql, params);
+  return rows;
+}
+
+export async function queryOne<T extends object = Record<string, unknown>>(
+  sql: string,
+  params?: unknown[]
+): Promise<T | null> {
+  const rows = await query<T>(sql, params);
+  return rows[0] ?? null;
+}