step 1: rename module chat-switchboard → switchboard-core

- go.mod module name
- All 714 import references across 289 Go files
- VERSION: 0.1.0
- CI DB names: switchboard_core_{ci,dev,test}
- Docker image: gobha/switchboard-core
- Test fixtures: JWT issuer, repo names
- .env.example, docker-compose container name
- Compiles clean (go build exit 0)

server/.env.example

@@ -18,7 +18,7 @@ DB_MAX_CONNS=25
 # ── Auth ─────────────────────────────────────
 JWT_SECRET=your-super-secret-jwt-key-change-in-production
 JWT_EXPIRATION=24h
-JWT_ISSUER=chat-switchboard
+JWT_ISSUER=switchboard-core
 
 # ── Bootstrap Admin ──────────────────────────
 # Creates or updates admin account on every startup.