Refactor Docker setup to integrate Web UI and streamline configuration

- Updated Dockerfile to build and embed the SvelteKit Web UI directly into the gateway image, eliminating the need for a separate web service.
- Modified .dockerignore to exclude unnecessary directories related to the web service.
- Adjusted config.compose.yaml to remove CORS settings for the web service, as the UI now shares the same origin as the API.
- Enhanced README.md to reflect the new single-port architecture for accessing both the Web UI and API.
- Removed the standalone web Dockerfile and updated related documentation for local development and build processes.

internal/server/gateway.go

@@ -17,6 +17,7 @@ import (
 	"github.com/telemt/telemt-api/internal/config"
 	"github.com/telemt/telemt-api/internal/geoip"
 	"github.com/telemt/telemt-api/internal/proxy"
+	"github.com/telemt/telemt-api/internal/webui"
 )
 
 // Gateway serves health, metrics, and proxied API routes.
@@ -29,6 +30,7 @@ type Gateway struct {
 	transport     *http.Transport
 	promHandler   http.Handler
 	corsAllowed   []string
+	webUI         http.Handler
 }
 
 // NewGateway builds handlers and reverse proxies from parsed config.
@@ -75,6 +77,7 @@ func NewGateway(p *config.Parsed, log *slog.Logger, geo *geoip.Service) (*Gatewa
 	}
 	g.corsAllowed = append([]string(nil), p.Config.CorsAllowedOrigins...)
 	g.agg = aggregate.NewHandler(p, &http.Client{Transport: t}, geo, aggCacheTTL)
+	g.webUI = webui.Handler()
 	return g, nil
 }
 
@@ -231,7 +234,7 @@ func (g *Gateway) serve(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	if !strings.HasPrefix(r.URL.Path, prefix) {
-		http.NotFound(w, r)
+		g.webUI.ServeHTTP(w, r)
 		return
 	}
 	trim := strings.TrimPrefix(r.URL.Path, prefix)