feat(ui): add standalone dashboard mode and relay switching (v0.52.2)

- Add standalone mode for dashboard to connect to any ORLY relay
- Implement relay switcher dropdown in header for standalone mode
- Add mobile drawer sidebar at 640px breakpoint with hamburger menu
- Add dedicated fallback pool for profile/relay list/contact list fetches
- Fix relay URL display to show host instead of NIP-11 name
- Add filter validation and defensive checks in event fetching
- Auto-expand search window from 30 days to 6 months on few results
- Add CORS support for API endpoints with configurable origins
- Fetch user relay list (NIP-65 kind 10002) and contact list on login
- Fix light mode user name color visibility in header

Files modified:
- app/config/config.go: Add CORS configuration options
- app/server.go: Add CORS middleware for API endpoints
- app/handle-relayinfo.go: Include CORS in relay info
- app/web/src/config.js: New config module for standalone mode
- app/web/src/stores.js: Add relay URL and standalone mode stores
- app/web/src/nostr.js: Add fallback pool, filter validation, relay/contact fetch
- app/web/src/Header.svelte: Relay dropdown, mobile menu, static indicator
- app/web/src/Sidebar.svelte: Mobile drawer mode with overlay
- app/web/src/App.svelte: Relay switching, mobile menu state, NIP-65 fetch
- app/web/src/api.js: Use configurable base URL
- app/web/src/constants.js: Add fallback relays, dynamic relay URLs
- cmd/dashboard-server/main.go: New standalone dashboard server

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cmd/dashboard-server/main.go

@@ -0,0 +1,70 @@
+// Simple static file server for testing the standalone dashboard
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+)
+
+func main() {
+	port := flag.Int("port", 8080, "port to listen on")
+	dir := flag.String("dir", "", "directory to serve (default: app/web/dist)")
+	flag.Parse()
+
+	// Find the dist directory
+	serveDir := *dir
+	if serveDir == "" {
+		// Try to find it relative to current directory or executable
+		candidates := []string{
+			"app/web/dist",
+			"../app/web/dist",
+			"../../app/web/dist",
+		}
+
+		// Also check relative to executable
+		if exe, err := os.Executable(); err == nil {
+			exeDir := filepath.Dir(exe)
+			candidates = append(candidates,
+				filepath.Join(exeDir, "app/web/dist"),
+				filepath.Join(exeDir, "../app/web/dist"),
+			)
+		}
+
+		for _, candidate := range candidates {
+			if info, err := os.Stat(candidate); err == nil && info.IsDir() {
+				serveDir = candidate
+				break
+			}
+		}
+
+		if serveDir == "" {
+			log.Fatal("Could not find dist directory. Use -dir flag to specify.")
+		}
+	}
+
+	absDir, _ := filepath.Abs(serveDir)
+	fmt.Printf("Serving %s on http://localhost:%d\n", absDir, *port)
+	fmt.Println("Press Ctrl+C to stop")
+
+	// Create file server with SPA fallback
+	fs := http.FileServer(http.Dir(serveDir))
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		// Try to serve the file
+		path := filepath.Join(serveDir, r.URL.Path)
+		if _, err := os.Stat(path); os.IsNotExist(err) {
+			// File doesn't exist, serve index.html for SPA routing
+			http.ServeFile(w, r, filepath.Join(serveDir, "index.html"))
+			return
+		}
+		fs.ServeHTTP(w, r)
+	})
+
+	addr := fmt.Sprintf(":%d", *port)
+	if err := http.ListenAndServe(addr, nil); err != nil {
+		log.Fatal(err)
+	}
+}