feat: Go backend, enhanced search, new widgets, Docker deploy

Major changes:
- Add Go backend (backend/) with microservices architecture
- Enhanced master-agents-svc: reranker, content-classifier, stealth-crawler,
  proxy-manager, media-search, fastClassifier, language detection
- New web-svc widgets: KnowledgeCard, ProductCard, ProfileCard, VideoCard,
  UnifiedCard, CardGallery, InlineImageGallery, SourcesPanel, RelatedQuestions
- Improved discover-svc with discover-db integration
- Docker deployment improvements (Caddyfile, vendor.sh, BUILD.md)
- Library-svc: project_id schema migration
- Remove deprecated finance-svc and travel-svc
- Localization improvements across services

Made-with: Cursor

backend/internal/search/searxng.go

@@ -0,0 +1,177 @@
+package search
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/gooseek/backend/internal/types"
+	"github.com/gooseek/backend/pkg/config"
+)
+
+type SearXNGClient struct {
+	primaryURL   string
+	fallbackURLs []string
+	client       *http.Client
+	timeout      time.Duration
+}
+
+func NewSearXNGClient(cfg *config.Config) *SearXNGClient {
+	return &SearXNGClient{
+		primaryURL:   cfg.SearXNGURL,
+		fallbackURLs: cfg.SearXNGFallbackURL,
+		client:       &http.Client{Timeout: cfg.SearchTimeout},
+		timeout:      cfg.SearchTimeout,
+	}
+}
+
+type SearchOptions struct {
+	Engines    []string
+	Categories []string
+	PageNo     int
+	Language   string
+}
+
+func (c *SearXNGClient) Search(ctx context.Context, query string, opts *SearchOptions) (*types.SearchResponse, error) {
+	candidates := c.buildCandidates()
+	if len(candidates) == 0 {
+		return nil, fmt.Errorf("no SearXNG URLs configured")
+	}
+
+	var lastErr error
+	for _, baseURL := range candidates {
+		result, err := c.searchWithURL(ctx, baseURL, query, opts)
+		if err == nil {
+			return result, nil
+		}
+		lastErr = err
+	}
+
+	return nil, fmt.Errorf("all SearXNG instances failed: %w", lastErr)
+}
+
+func (c *SearXNGClient) buildCandidates() []string {
+	candidates := make([]string, 0)
+
+	if c.primaryURL != "" {
+		u := strings.TrimSuffix(c.primaryURL, "/")
+		if !strings.HasPrefix(u, "http") {
+			u = "http://" + u
+		}
+		candidates = append(candidates, u)
+	}
+
+	for _, fb := range c.fallbackURLs {
+		u := strings.TrimSpace(fb)
+		if u == "" {
+			continue
+		}
+		u = strings.TrimSuffix(u, "/")
+		if !strings.HasPrefix(u, "http") {
+			u = "https://" + u
+		}
+		if !contains(candidates, u) {
+			candidates = append(candidates, u)
+		}
+	}
+
+	return candidates
+}
+
+func (c *SearXNGClient) searchWithURL(ctx context.Context, baseURL, query string, opts *SearchOptions) (*types.SearchResponse, error) {
+	params := url.Values{}
+	params.Set("format", "json")
+	params.Set("q", query)
+
+	if opts != nil {
+		if len(opts.Engines) > 0 {
+			params.Set("engines", strings.Join(opts.Engines, ","))
+		}
+		if len(opts.Categories) > 0 {
+			params.Set("categories", strings.Join(opts.Categories, ","))
+		}
+		if opts.PageNo > 0 {
+			params.Set("pageno", fmt.Sprintf("%d", opts.PageNo))
+		}
+		if opts.Language != "" {
+			params.Set("language", opts.Language)
+		}
+	}
+
+	reqURL := fmt.Sprintf("%s/search?%s", baseURL, params.Encode())
+
+	req, err := http.NewRequestWithContext(ctx, "GET", reqURL, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := c.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("SearXNG returned status %d", resp.StatusCode)
+	}
+
+	var result struct {
+		Results     []types.SearchResult `json:"results"`
+		Suggestions []string             `json:"suggestions"`
+	}
+
+	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
+		return nil, err
+	}
+
+	return &types.SearchResponse{
+		Results:     result.Results,
+		Suggestions: result.Suggestions,
+	}, nil
+}
+
+var (
+	productPattern   = regexp.MustCompile(`ozon\.ru/product|wildberries\.ru/catalog/\d|aliexpress\.(ru|com)/item|market\.yandex`)
+	videoPattern     = regexp.MustCompile(`rutube\.ru/video|vk\.com/video|vk\.com/clip|youtube\.com/watch|youtu\.be|dzen\.ru/video`)
+	vkProfilePattern = regexp.MustCompile(`vk\.com/[a-zA-Z0-9_.]+$`)
+	tgProfilePattern = regexp.MustCompile(`t\.me/[a-zA-Z0-9_]+$`)
+)
+
+func CategorizeResult(result *types.SearchResult) types.ContentCategory {
+	urlLower := strings.ToLower(result.URL)
+
+	if productPattern.MatchString(urlLower) {
+		return types.CategoryProduct
+	}
+
+	if videoPattern.MatchString(urlLower) || result.IframeSrc != "" || result.Category == "videos" {
+		return types.CategoryVideo
+	}
+
+	if tgProfilePattern.MatchString(urlLower) {
+		return types.CategoryProfile
+	}
+	if vkProfilePattern.MatchString(urlLower) && !videoPattern.MatchString(urlLower) {
+		return types.CategoryProfile
+	}
+
+	if result.ImgSrc != "" && result.Category == "images" {
+		return types.CategoryImage
+	}
+
+	return types.CategoryArticle
+}
+
+func contains(slice []string, item string) bool {
+	for _, s := range slice {
+		if s == item {
+			return true
+		}
+	}
+	return false
+}