feat: integrate React frontend with Go backend and containerize with Docker

- Rewrite Dockerfile with 4-stage build process:
  - Stage 1: Build React SPA with Bun (oven/bun:latest)
  - Stage 2: Build Go binary with embedded frontend (golang:1.25-alpine)
  - Stage 3: Fetch runtime dependencies (alpine:3.23)
  - Stage 4: Minimal runtime container (busybox:1.37.0-musl)
- Add comprehensive comments explaining each build stage
- Add build verification checks to ensure frontend embeds correctly
- Update compose.yaml with environment variables (FB_PORT=80, FB_ADDRESS=0.0.0.0)
- Add docker-compose.dev.yaml for development with hot reload support
- Modify http/static.go to serve 'index.html' instead of 'public/index.html'
- Final production image: ~50MB with non-root user and health checks
- Enable both production and development Docker workflows

http/static.go

@@ -1,12 +1,12 @@
 package fbhttp
 
 import (
+	"compress/gzip"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/fs"
 	"io"
-	"compress/gzip"
+	"io/fs"
 	"log"
 	"net/http"
 	"os"
@@ -110,7 +110,7 @@ func getStaticHandlers(store *storage.Storage, server *settings.Server, assetsFs
 		}
 
 		w.Header().Set("x-xss-protection", "1; mode=block")
-		return handleWithStaticData(w, r, d, assetsFs, "public/index.html", "text/html; charset=utf-8")
+		return handleWithStaticData(w, r, d, assetsFs, "index.html", "text/html; charset=utf-8")
 	}, "", store, server)
 
 	static = handle(func(w http.ResponseWriter, r *http.Request, d *data) (int, error) {
@@ -153,7 +153,7 @@ func getStaticHandlers(store *storage.Storage, server *settings.Server, assetsFs
 		defer f.Close()
 
 		acceptEncoding := r.Header.Get("Accept-Encoding")
-		if strings.Contains(acceptEncoding, "gzip") {		
+		if strings.Contains(acceptEncoding, "gzip") {
 			w.Header().Set("Content-Encoding", "gzip")
 			w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
 
@@ -168,7 +168,7 @@ func getStaticHandlers(store *storage.Storage, server *settings.Server, assetsFs
 			defer gzReader.Close()
 
 			w.Header().Set("Content-Type", "application/javascript; charset=utf-8")
-			
+
 			if _, err := io.Copy(w, gzReader); err != nil {
 				return http.StatusInternalServerError, err
 			}