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/middleware/prometheus.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/gin-gonic/gin"
 
-	"chat-switchboard/metrics"
+	"switchboard-core/metrics"
 )
 
 // Prometheus returns a Gin middleware that records HTTP request metrics.