feat: rename Docker Watcher to Tinyforge

Rebrand the project as Tinyforge to reflect its evolution from a Docker
container watcher into a self-hosted mini CI/deployment platform.

Rename covers: Go module path, Docker labels, DB/config filenames,
JWT issuer, Dockerfile binary, docker-compose, CI workflows, frontend
i18n, README with static sites docs, and all code comments.

internal/docker/client.go

@@ -7,11 +7,11 @@ import (
 	"github.com/moby/moby/client"
 )
 
-// Labels applied to all containers managed by docker-watcher.
+// Labels applied to all containers managed by Tinyforge.
 const (
-	LabelProject    = "docker-watcher.project"
-	LabelStage      = "docker-watcher.stage"
-	LabelInstanceID = "docker-watcher.instance-id"
+	LabelProject    = "tinyforge.project"
+	LabelStage      = "tinyforge.stage"
+	LabelInstanceID = "tinyforge.instance-id"
 )
 
 // Client wraps the Docker Engine API client.