feat: initialize project skeleton with Go backend, database, and config

- Go module with standard library + gorilla/sessions + mysql driver
- Config: env-based configuration with .env file support
- Database: MySQL connection with auto-migration for 6 tables
- Seed data: 12 system tags with options, 8 system snippets
- Auth: session cookie middleware
- Handlers: auth, tags, snippets, builder, claude, dashboard, suggestions, settings
- LLM: OpenAI-compatible client with 30s timeout
- Docker: Dockerfile + docker-compose.yml
- .env.example with all configuration options

Co-Authored-By: Claude <noreply@anthropic.com>

main.go

@@ -0,0 +1,133 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+
+	"prompt-generator/internal/auth"
+	"prompt-generator/internal/config"
+	"prompt-generator/internal/db"
+	"prompt-generator/internal/handlers"
+)
+
+func main() {
+	// Load .env file if exists
+	loadEnvFile(".env")
+
+	cfg := config.Load()
+
+	// Initialize database
+	if err := db.Init(cfg); err != nil {
+		log.Fatalf("Failed to initialize database: %v", err)
+	}
+
+	// Auto migrate
+	if err := db.AutoMigrate(); err != nil {
+		log.Fatalf("Failed to migrate database: %v", err)
+	}
+
+	// Seed data
+	if err := db.SeedData(); err != nil {
+		log.Fatalf("Failed to seed data: %v", err)
+	}
+
+	// Initialize auth
+	auth.Init(cfg.SessionSecret)
+
+	// Initialize handlers
+	handlers.Init(cfg)
+
+	// Setup routes
+	mux := http.NewServeMux()
+
+	// Static files (frontend)
+	fs := http.FileServer(http.Dir("frontend"))
+	mux.Handle("/", fs)
+
+	// Auth routes (no auth required)
+	mux.HandleFunc("POST /api/auth/login", handlers.Login)
+	mux.HandleFunc("POST /api/auth/logout", handlers.Logout)
+	mux.HandleFunc("GET /api/auth/check", handlers.AuthCheck)
+
+	// Protected API routes
+	apiMux := http.NewServeMux()
+	apiMux.HandleFunc("GET /api/tags", handlers.GetTags)
+	apiMux.HandleFunc("POST /api/tags", handlers.CreateTag)
+	apiMux.HandleFunc("PUT /api/tags/{id}", handlers.UpdateTag)
+	apiMux.HandleFunc("DELETE /api/tags/{id}", handlers.DeleteTag)
+	apiMux.HandleFunc("POST /api/tags/{id}/options", handlers.CreateTagOption)
+	apiMux.HandleFunc("PUT /api/tag-options/{id}", handlers.UpdateTagOption)
+	apiMux.HandleFunc("DELETE /api/tag-options/{id}", handlers.DeleteTagOption)
+
+	apiMux.HandleFunc("GET /api/snippets", handlers.GetSnippets)
+	apiMux.HandleFunc("POST /api/snippets", handlers.CreateSnippet)
+	apiMux.HandleFunc("PUT /api/snippets/{id}", handlers.UpdateSnippet)
+	apiMux.HandleFunc("DELETE /api/snippets/{id}", handlers.DeleteSnippet)
+
+	apiMux.HandleFunc("GET /api/builder/sessions", handlers.GetBuilderSessions)
+	apiMux.HandleFunc("POST /api/builder/sessions", handlers.CreateBuilderSession)
+	apiMux.HandleFunc("GET /api/builder/sessions/{id}", handlers.GetBuilderSession)
+	apiMux.HandleFunc("PUT /api/builder/sessions/{id}", handlers.UpdateBuilderSession)
+	apiMux.HandleFunc("DELETE /api/builder/sessions/{id}", handlers.DeleteBuilderSession)
+
+	apiMux.HandleFunc("GET /api/claude/sessions", handlers.GetClaudeSessions)
+	apiMux.HandleFunc("GET /api/claude/sessions/{session_id}/prompts", handlers.GetClaudePrompts)
+
+	apiMux.HandleFunc("GET /api/dashboard/projects", handlers.GetDashboardProjects)
+	apiMux.HandleFunc("GET /api/dashboard/projects/{name}/sessions", handlers.GetDashboardSessions)
+	apiMux.HandleFunc("GET /api/dashboard/prompts", handlers.GetDashboardPrompts)
+
+	apiMux.HandleFunc("POST /api/suggestions", handlers.GetSuggestions)
+
+	apiMux.HandleFunc("GET /api/settings", handlers.GetSettings)
+	apiMux.HandleFunc("PUT /api/settings", handlers.UpdateSettings)
+
+	// Wrap API routes with auth middleware
+	mux.Handle("/api/", auth.AuthMiddleware(apiMux))
+
+	log.Printf("Server starting on :%s", cfg.ServerPort)
+	if err := http.ListenAndServe(":"+cfg.ServerPort, mux); err != nil {
+		log.Fatalf("Server failed: %v", err)
+	}
+}
+
+func loadEnvFile(path string) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return // .env file is optional
+	}
+	lines := splitLines(string(data))
+	for _, line := range lines {
+		if len(line) == 0 || line[0] == '#' {
+			continue
+		}
+		for i := 0; i < len(line); i++ {
+			if line[i] == '=' {
+				key := line[:i]
+				value := line[i+1:]
+				// Remove quotes
+				if len(value) >= 2 && (value[0] == '"' && value[len(value)-1] == '"') {
+					value = value[1 : len(value)-1]
+				}
+				os.Setenv(key, value)
+				break
+			}
+		}
+	}
+}
+
+func splitLines(s string) []string {
+	var lines []string
+	start := 0
+	for i := 0; i < len(s); i++ {
+		if s[i] == '\n' {
+			lines = append(lines, s[start:i])
+			start = i + 1
+		}
+	}
+	if start < len(s) {
+		lines = append(lines, s[start:])
+	}
+	return lines
+}