rename: homelab-gateway → telegram-gateway

Aligns the project name with the public URL (tg.arcodange.fr) and the
Arcodange organization conventions. The 'homelab-gateway' name was too
generic.

Touches: chart name + helpers, image registry path, Go module path,
secret/configmap names, deployment mountPath, all docs.

main.go

@@ -13,7 +13,7 @@ import (
 )
 
 const defaultListenAddr = ":8080"
-const defaultConfigPath = "/etc/homelab-gateway/bots.yaml"
+const defaultConfigPath = "/etc/telegram-gateway/bots.yaml"
 
 func main() {
 	subcmd := ""
@@ -62,7 +62,7 @@ func runServer() {
 	defer stop()
 
 	go func() {
-		log.Printf("homelab-gateway listening on %s (%d bot(s) loaded)", *addr, registry.Count())
+		log.Printf("telegram-gateway listening on %s (%d bot(s) loaded)", *addr, registry.Count())
 		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
 			log.Fatalf("server: %v", err)
 		}