feat: migrate from env vars to config.toml

- Add internal/config package with TOML parsing (BurntSushi/toml)
- Create config.example.toml documenting all settings
- Update main.go to load config via -config flag (default: config.toml)
- Environment variables remain as fallback overrides for backward compat
- Config file values are used as defaults; env vars override when set
- Add comprehensive tests for file loading, defaults, and env overrides
- Add config.toml to .gitignore (secrets stay local)

cmd/searxng-go/main.go

@@ -1,33 +1,42 @@
 package main
 
 import (
+	"flag"
+	"fmt"
 	"log"
 	"net/http"
 	"os"
-	"time"
 
+	"github.com/ashie/gosearch/internal/config"
 	"github.com/ashie/gosearch/internal/httpapi"
 	"github.com/ashie/gosearch/internal/search"
 )
 
 func main() {
-	port := os.Getenv("PORT")
-	if port == "" {
-		port = "8080"
+	configPath := flag.String("config", "config.toml", "path to config.toml")
+	flag.Parse()
+
+	cfg, err := config.Load(*configPath)
+	if err != nil {
+		log.Fatalf("failed to load config: %v", err)
 	}
 
-	upstreamURL := os.Getenv("UPSTREAM_SEARXNG_URL")
-
-	timeout := 10 * time.Second
-	if v := os.Getenv("HTTP_TIMEOUT"); v != "" {
-		if d, err := time.ParseDuration(v); err == nil {
-			timeout = d
-		}
+	// Seed env vars from config so existing engine/factory/planner code
+	// picks them up without changes. The config layer is the single source
+	// of truth; env vars remain as overrides via applyEnvOverrides.
+	if len(cfg.Engines.LocalPorted) > 0 {
+		os.Setenv("LOCAL_PORTED_ENGINES", cfg.LocalPortedCSV())
+	}
+	if cfg.Engines.Brave.APIKey != "" {
+		os.Setenv("BRAVE_API_KEY", cfg.Engines.Brave.APIKey)
+	}
+	if cfg.Engines.Brave.AccessToken != "" {
+		os.Setenv("BRAVE_ACCESS_TOKEN", cfg.Engines.Brave.AccessToken)
 	}
 
 	svc := search.NewService(search.ServiceConfig{
-		UpstreamURL: upstreamURL,
-		HTTPTimeout: timeout,
+		UpstreamURL: cfg.Upstream.URL,
+		HTTPTimeout: cfg.HTTPTimeout(),
 	})
 
 	h := httpapi.NewHandler(svc)
@@ -36,8 +45,7 @@ func main() {
 	mux.HandleFunc("/healthz", h.Healthz)
 	mux.HandleFunc("/search", h.Search)
 
-	addr := ":" + port
+	addr := fmt.Sprintf(":%d", cfg.Server.Port)
 	log.Printf("searxng-go listening on %s", addr)
 	log.Fatal(http.ListenAndServe(addr, mux))
 }
-