feat(k8s): add K8s manifests for all homelab services

traefik, gitea, adguard, nextcloud, errorpages, homepages,
uptime-kuma, kener, checkmk, headscale, dockmon, metube,
downtify, portainer, netronome, userbot

Includes Helm values, deployments, services, ingress routes,
configmaps, secrets (placeholders), postgres statefulsets,
kustomize overlays, and Traefik dynamic configuration.

gitea/k8s/config.yaml

@@ -0,0 +1,20 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: gitea-config
+  namespace: gitea
+data:
+  GITEA__server__DOMAIN: "gitea.gigaforust.internal"
+  GITEA__server__ROOT_URL: "https://gitea.gigaforust.internal"
+  GITEA__server__SSH_DOMAIN: "gitssh.gigaforust.internal"
+  GITEA__server__SSH_PORT: "2221"
+
+  GITEA__database__DB_TYPE: "postgres"
+  GITEA__database__HOST: "gitea-postgres-service:5432"
+  GITEA__database__NAME: "gitea"
+  GITEA__security__REVERSE_PROXY_LIMIT: "1"
+  GITEA__security__REVERSE_PROXY_TRUSTED_PROXIES: "*"
+  
+  GITEA__mailer__ENABLED: "false"
+  USER_UID: "1000"
+  USER_GID: "1000"