feat: migrate to Gitea, productize Helm chart, unify version

- CI: replace GitLab pipeline with Gitea Actions (.gitea/workflows/release.yaml);
  publish .deb/image/hosted/chart to Gitea registries; gate image+hosted on .deb
  (needs + registry pre-check)
- drop connectone/Nexus; apt now from the Gitea Debian registry
- single version source (/VERSION=3.2.8); CI enforces .env/Chart consistency
- restructure: build/->packaging/deb, root Dockerfile->packaging/image,
  hosted/->packaging/hosted, .kube/->charts/freeradius
- Helm chart: documented values, DB password via Secret/$ENV, configurable
  scheduling/persistence; remove plaintext creds and hostPath PV
- gitignore *.env_cnf; docs for hosted (RU)/helm/root + agent KB sync

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packaging/hosted/.env_cnf_example

@@ -0,0 +1,9 @@
+FR_MAIN_PORT=31812
+FR_ACC_PORT=31813
+FR_API_HOST=<MAIN_IP>
+FR_API_PORT=31668
+FR_PG_HOST=<MAIN_IP>
+FR_PG_PORT=32207
+FR_PG_USER=admin
+FR_PG_PASS=<DATABASE_PASSWORD>
+FR_PG_DB=radius_db