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/backup/engine.go

@@ -8,7 +8,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/alexei/docker-watcher/internal/store"
+	"github.com/alexei/tinyforge/internal/store"
 )
 
 // Engine manages database backup operations.
@@ -52,7 +52,7 @@ func (e *Engine) CreateBackup(backupType string) (store.Backup, error) {
 	defer e.mu.Unlock()
 
 	timestamp := time.Now().UTC().Format("20060102-150405")
-	filename := fmt.Sprintf("docker-watcher-%s-%s.db", backupType, timestamp)
+	filename := fmt.Sprintf("tinyforge-%s-%s.db", backupType, timestamp)
 	destPath := filepath.Join(e.backupDir, filename)
 
 	// VACUUM INTO creates a clean, standalone copy of the database.