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/db/postgres.go

@@ -0,0 +1,134 @@
+package db
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"time"
+
+	_ "github.com/lib/pq"
+)
+
+type PostgresDB struct {
+	db *sql.DB
+}
+
+func NewPostgresDB(databaseURL string) (*PostgresDB, error) {
+	db, err := sql.Open("postgres", databaseURL)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open database: %w", err)
+	}
+
+	db.SetMaxOpenConns(25)
+	db.SetMaxIdleConns(5)
+	db.SetConnMaxLifetime(5 * time.Minute)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	if err := db.PingContext(ctx); err != nil {
+		return nil, fmt.Errorf("failed to ping database: %w", err)
+	}
+
+	return &PostgresDB{db: db}, nil
+}
+
+func (p *PostgresDB) Close() error {
+	return p.db.Close()
+}
+
+func (p *PostgresDB) DB() *sql.DB {
+	return p.db
+}
+
+func (p *PostgresDB) RunMigrations(ctx context.Context) error {
+	migrations := []string{
+		`CREATE TABLE IF NOT EXISTS digests (
+			id SERIAL PRIMARY KEY,
+			topic VARCHAR(100) NOT NULL,
+			region VARCHAR(50) NOT NULL,
+			cluster_title VARCHAR(500) NOT NULL,
+			summary_ru TEXT NOT NULL,
+			citations JSONB DEFAULT '[]',
+			sources_count INT DEFAULT 0,
+			follow_up JSONB DEFAULT '[]',
+			thumbnail TEXT,
+			short_description TEXT,
+			main_url TEXT,
+			created_at TIMESTAMPTZ DEFAULT NOW(),
+			updated_at TIMESTAMPTZ DEFAULT NOW(),
+			UNIQUE(topic, region, cluster_title)
+		)`,
+		`CREATE INDEX IF NOT EXISTS idx_digests_topic_region ON digests(topic, region)`,
+		`CREATE INDEX IF NOT EXISTS idx_digests_main_url ON digests(main_url)`,
+		`CREATE TABLE IF NOT EXISTS article_summaries (
+			id SERIAL PRIMARY KEY,
+			url_hash VARCHAR(64) NOT NULL UNIQUE,
+			url TEXT NOT NULL,
+			events JSONB NOT NULL DEFAULT '[]',
+			created_at TIMESTAMPTZ DEFAULT NOW(),
+			expires_at TIMESTAMPTZ DEFAULT NOW() + INTERVAL '7 days'
+		)`,
+		`CREATE INDEX IF NOT EXISTS idx_article_summaries_url_hash ON article_summaries(url_hash)`,
+		`CREATE INDEX IF NOT EXISTS idx_article_summaries_expires ON article_summaries(expires_at)`,
+		`CREATE TABLE IF NOT EXISTS collections (
+			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+			user_id UUID NOT NULL,
+			name VARCHAR(255) NOT NULL,
+			description TEXT,
+			is_public BOOLEAN DEFAULT FALSE,
+			context_enabled BOOLEAN DEFAULT TRUE,
+			created_at TIMESTAMPTZ DEFAULT NOW(),
+			updated_at TIMESTAMPTZ DEFAULT NOW()
+		)`,
+		`CREATE INDEX IF NOT EXISTS idx_collections_user ON collections(user_id)`,
+		`CREATE TABLE IF NOT EXISTS collection_items (
+			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+			collection_id UUID NOT NULL REFERENCES collections(id) ON DELETE CASCADE,
+			item_type VARCHAR(50) NOT NULL,
+			title VARCHAR(500),
+			content TEXT,
+			url TEXT,
+			metadata JSONB DEFAULT '{}',
+			created_at TIMESTAMPTZ DEFAULT NOW(),
+			sort_order INT DEFAULT 0
+		)`,
+		`CREATE INDEX IF NOT EXISTS idx_collection_items_collection ON collection_items(collection_id)`,
+		`CREATE TABLE IF NOT EXISTS uploaded_files (
+			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+			user_id UUID NOT NULL,
+			filename VARCHAR(500) NOT NULL,
+			file_type VARCHAR(100) NOT NULL,
+			file_size BIGINT NOT NULL,
+			storage_path TEXT NOT NULL,
+			extracted_text TEXT,
+			metadata JSONB DEFAULT '{}',
+			created_at TIMESTAMPTZ DEFAULT NOW()
+		)`,
+		`CREATE INDEX IF NOT EXISTS idx_uploaded_files_user ON uploaded_files(user_id)`,
+		`CREATE TABLE IF NOT EXISTS research_sessions (
+			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+			user_id UUID,
+			collection_id UUID REFERENCES collections(id) ON DELETE SET NULL,
+			query TEXT NOT NULL,
+			focus_mode VARCHAR(50) DEFAULT 'all',
+			optimization_mode VARCHAR(50) DEFAULT 'balanced',
+			sources JSONB DEFAULT '[]',
+			response_blocks JSONB DEFAULT '[]',
+			final_answer TEXT,
+			citations JSONB DEFAULT '[]',
+			created_at TIMESTAMPTZ DEFAULT NOW(),
+			completed_at TIMESTAMPTZ
+		)`,
+		`CREATE INDEX IF NOT EXISTS idx_research_sessions_user ON research_sessions(user_id)`,
+		`CREATE INDEX IF NOT EXISTS idx_research_sessions_collection ON research_sessions(collection_id)`,
+	}
+
+	for _, migration := range migrations {
+		if _, err := p.db.ExecContext(ctx, migration); err != nil {
+			return fmt.Errorf("migration failed: %w", err)
+		}
+	}
+
+	return nil
+}