refactor: merge gateway functionality into frontend container

Eliminated duplicate nginx containers by merging gateway reverse proxy
functionality into the frontend container. This simplifies deployment
and reduces resource usage.

Architecture changes:
- Frontend now serves both static files AND reverse proxies to backend
- Single nginx container handles all HTTP routing
- Gateway container removed from builds and Helm chart

Dockerfile.frontend changes:
- Added upstream backend configuration
- Added proxy locations for /api, /health, /metrics, /npm, /pypi, /go, /ws
- Added rate limiting for API and downloads
- Added WebSocket support
- Configurable via BACKEND_HOST and BACKEND_PORT env vars

Helm chart changes:
- Updated frontend deployment to configure backend connection
- Simplified ingress to single route (all traffic → frontend)
- Frontend proxies backend requests internally
- Removed separate frontend/api ingress configurations

GoReleaser changes:
- Removed gohoarder-gateway Docker build
- Now builds: server, scanner, migrate, frontend (4 images)

Benefits:
- Fewer containers to manage
- Reduced complexity in Docker Compose and Kubernetes
- Single point of configuration for routing
- Better resource utilization

helm/gohoarder/templates/ingress.yaml

@@ -1,11 +1,10 @@
 {{- if .Values.ingress.enabled -}}
-{{- if .Values.ingress.frontend.enabled -}}
 apiVersion: networking.k8s.io/v1
 kind: Ingress
 metadata:
-  name: {{ include "gohoarder.fullname" . }}-frontend
+  name: {{ include "gohoarder.fullname" . }}
   labels:
-    {{- include "gohoarder.frontend.labels" . | nindent 4 }}
+    {{- include "gohoarder.labels" . | nindent 4 }}
   {{- with .Values.ingress.annotations }}
   annotations:
     {{- toYaml . | nindent 4 }}
@@ -14,65 +13,17 @@ spec:
   {{- if .Values.ingress.className }}
   ingressClassName: {{ .Values.ingress.className }}
   {{- end }}
-  {{- if .Values.ingress.frontend.tls.enabled }}
+  {{- if .Values.ingress.tls.enabled }}
   tls:
     - hosts:
-        - {{ .Values.ingress.frontend.host | default (printf "%s.%s" "gohoarder" .Values.global.domain) | quote }}
-      secretName: {{ .Values.ingress.frontend.tls.secretName }}
+        - {{ .Values.ingress.host | default (printf "%s.%s" "gohoarder" .Values.global.domain) | quote }}
+      secretName: {{ .Values.ingress.tls.secretName }}
   {{- end }}
   rules:
-    - host: {{ .Values.ingress.frontend.host | default (printf "%s.%s" "gohoarder" .Values.global.domain) | quote }}
+    - host: {{ .Values.ingress.host | default (printf "%s.%s" "gohoarder" .Values.global.domain) | quote }}
       http:
         paths:
-          - path: /npm
-            pathType: Prefix
-            backend:
-              service:
-                name: {{ include "gohoarder.fullname" . }}-server
-                port:
-                  number: {{ .Values.server.service.port }}
-          - path: /pypi
-            pathType: Prefix
-            backend:
-              service:
-                name: {{ include "gohoarder.fullname" . }}-server
-                port:
-                  number: {{ .Values.server.service.port }}
-          - path: /go
-            pathType: Prefix
-            backend:
-              service:
-                name: {{ include "gohoarder.fullname" . }}-server
-                port:
-                  number: {{ .Values.server.service.port }}
-          - path: /api
-            pathType: Prefix
-            backend:
-              service:
-                name: {{ include "gohoarder.fullname" . }}-server
-                port:
-                  number: {{ .Values.server.service.port }}
-          - path: /ws
-            pathType: Prefix
-            backend:
-              service:
-                name: {{ include "gohoarder.fullname" . }}-server
-                port:
-                  number: {{ .Values.server.service.port }}
-          - path: /health
-            pathType: Prefix
-            backend:
-              service:
-                name: {{ include "gohoarder.fullname" . }}-server
-                port:
-                  number: {{ .Values.server.service.port }}
-          - path: /metrics
-            pathType: Prefix
-            backend:
-              service:
-                name: {{ include "gohoarder.fullname" . }}-server
-                port:
-                  number: {{ .Values.server.service.port }}
+          # Route all traffic to frontend (which now includes reverse proxy to backend)
           - path: /
             pathType: Prefix
             backend:
@@ -81,38 +32,3 @@ spec:
                 port:
                   number: {{ .Values.frontend.service.port }}
 {{- end }}
----
-{{- if .Values.ingress.api.enabled }}
-apiVersion: networking.k8s.io/v1
-kind: Ingress
-metadata:
-  name: {{ include "gohoarder.fullname" . }}-api
-  labels:
-    {{- include "gohoarder.server.labels" . | nindent 4 }}
-  {{- with .Values.ingress.annotations }}
-  annotations:
-    {{- toYaml . | nindent 4 }}
-  {{- end }}
-spec:
-  {{- if .Values.ingress.className }}
-  ingressClassName: {{ .Values.ingress.className }}
-  {{- end }}
-  {{- if .Values.ingress.api.tls.enabled }}
-  tls:
-    - hosts:
-        - {{ .Values.ingress.api.host | default (printf "api.%s.%s" "gohoarder" .Values.global.domain) | quote }}
-      secretName: {{ .Values.ingress.api.tls.secretName }}
-  {{- end }}
-  rules:
-    - host: {{ .Values.ingress.api.host | default (printf "api.%s.%s" "gohoarder" .Values.global.domain) | quote }}
-      http:
-        paths:
-          - path: /
-            pathType: Prefix
-            backend:
-              service:
-                name: {{ include "gohoarder.fullname" . }}-server
-                port:
-                  number: {{ .Values.server.service.port }}
-{{- end }}
-{{- end }}