Rename project from imc-vibe to imc

- Binary name: imc-vibe -> imc
- Go module: github.com/imc-vibe/backend -> github.com/imc/backend
- JWT issuer: imc-vibe -> imc
- UI labels: IMC Vibe -> IMC
- Update all imports and comments

backend/internal/api/handlers/queue.go

@@ -5,7 +5,7 @@ import (
 	"net/http"
 
 	"github.com/gin-gonic/gin"
-	"github.com/imc-vibe/backend/internal/mail"
+	"github.com/imc/backend/internal/mail"
 )
 
 type QueueHandler struct{}