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/gitea.go

@@ -41,6 +41,80 @@ func NewGiteaClient(baseURL, token string) *GiteaClient {
 	}
 }
 
+// ListImages returns all container images (packages) for the given owner.
+// It queries GET /api/v1/packages/{owner}?type=container and paginates
+// through all results, returning a RegistryImage for each unique package.
+func (c *GiteaClient) ListImages(ctx context.Context, owner string) ([]RegistryImage, error) {
+	if owner == "" {
+		return nil, fmt.Errorf("owner is required for listing images")
+	}
+
+	// Extract the registry host from baseURL to build full references.
+	host := c.baseURL
+	for _, prefix := range []string{"https://", "http://"} {
+		host = strings.TrimPrefix(host, prefix)
+	}
+	host = strings.TrimRight(host, "/")
+
+	var images []RegistryImage
+	seen := make(map[string]bool)
+	page := 1
+	limit := 50
+
+	for {
+		url := fmt.Sprintf("%s/api/v1/packages/%s?type=container&page=%d&limit=%d",
+			c.baseURL, owner, page, limit)
+
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+		if err != nil {
+			return nil, fmt.Errorf("create request: %w", err)
+		}
+
+		if c.token != "" {
+			req.Header.Set("Authorization", "token "+c.token)
+		}
+		req.Header.Set("Accept", "application/json")
+
+		resp, err := c.httpClient.Do(req)
+		if err != nil {
+			return nil, fmt.Errorf("execute request: %w", err)
+		}
+
+		body, err := io.ReadAll(resp.Body)
+		resp.Body.Close()
+		if err != nil {
+			return nil, fmt.Errorf("read response body: %w", err)
+		}
+
+		if resp.StatusCode != http.StatusOK {
+			return nil, fmt.Errorf("unexpected status %d: %s", resp.StatusCode, string(body))
+		}
+
+		var packages []giteaPackageListEntry
+		if err := json.Unmarshal(body, &packages); err != nil {
+			return nil, fmt.Errorf("decode package list: %w", err)
+		}
+
+		for _, p := range packages {
+			if !seen[p.Name] {
+				seen[p.Name] = true
+				images = append(images, RegistryImage{
+					Name:    p.Name,
+					Owner:   owner,
+					FullRef: fmt.Sprintf("%s/%s/%s", host, owner, p.Name),
+				})
+			}
+		}
+
+		if len(packages) < limit {
+			break
+		}
+		page++
+	}
+
+	return images, nil
+}
+
 // ListTags returns all available tags for the given container image.
 // The image should be in the format "owner/package-name" or
 // "registry-host/owner/package-name" (the registry host prefix is stripped).

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