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/sandbox/provider_module.go

@@ -32,7 +32,7 @@ import (
 	"go.starlark.net/starlark"
 	"go.starlark.net/starlarkstruct"
 
-	"chat-switchboard/providers"
+	"switchboard-core/providers"
 )
 
 // ─── Provider Resolution Interface ──────────