c9c72be0b6
PR 4a of the runtime service registry change. - Remove addon pages (/addons/:addonId, AddonPage, addons/*) superseded by service pages. - Remove grafana_url/prometheus_url from backend config, compose, .env.example, and README (URLs now live on service records; VITE_ frontend deep-link vars retained). - Add Services page (/services) with create/list/delete + sidebar nav, so services are configurable in the tool itself and service pages are reachable. - Update docs/REQUIREMENTS.md service-registry section; add CHANGELOG.md with the breaking-upgrade note (MANAGE_ENCRYPTION_KEY required; grafana/prometheus env vars removed; default widget seeding removed). Verification: backend ruff clean, pytest 222 passed; frontend lint 0 errors, build success, 70 tests passed.