feat: auto-discover container images from registries

- Add ListImages() to registry interface, implement for Gitea
- Add owner field to registry config (needed for Gitea packages API)
- GET /api/registries/:id/images endpoint
- "Browse Images" button on Projects and Quick Deploy pages
- Image dropdown with registry grouping and search
- i18n support (EN/RU) for all new UI strings

internal/registry/registry.go

@@ -8,6 +8,13 @@ import (
 	"strings"
 )
 
+// RegistryImage represents a container image discovered from a registry.
+type RegistryImage struct {
+	Name    string `json:"name"`
+	Owner   string `json:"owner"`
+	FullRef string `json:"full_ref"` // e.g., "git.example.com/owner/my-app"
+}
+
 // Client defines the interface for interacting with a container image registry.
 type Client interface {
 	// ListTags returns all available tags for the given image.
@@ -16,6 +23,10 @@ type Client interface {
 	// GetLatestTag returns the most recently created tag that matches the given
 	// glob pattern. Returns an empty string and no error if no tags match.
 	GetLatestTag(ctx context.Context, image string, pattern string) (string, error)
+
+	// ListImages returns all container images available in the registry for the
+	// given owner. Returns an error if the registry does not support image listing.
+	ListImages(ctx context.Context, owner string) ([]RegistryImage, error)
 }
 
 // DeployTriggerer is called by the poller when a new tag is detected for a