chore(renovate): hand-migrate docker key, track gitea/runner, keep range lower bounds

- Replace the deprecated top-level `docker` key with the packageRule Renovate's
  own migration produced (matchCategories docker, enabled true), keeping every
  comment. Supersedes #139, which dropped all comment lines.
- Add gitea/runner (act_runner's upstream rename) to the blast-radius rule.
- rangeStrategy bump for flux/helm `>=A <B` ranges: the default `auto` resolves
  to `replace`, which turned `>=1.12.0 <1.13.0` into `<1.14.0` (#131, #130,
  #115). In-range `bump` updates are disabled; Flux adopts those unaided.
- Restore headlamp's lower bound: `<0.47.0` -> `>=0.46.0 <0.47.0` (live 0.46.0).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

platform/headlamp/helmrelease.yaml

@@ -40,7 +40,11 @@ spec:
       # values (-session-ttl + the -oidc-* args from the externalSecret; useCookie stays default-false
       # so `-oidc-use-cookie` is NOT emitted) is supported by the v0.41.0 backend. Renovate maintains
       # within 0.41.x; the appVersion continues to pin the Headlamp image.
-      version: "<0.47.0"
+      # 2026-11-08: NOW 0.46.x. PR #130 (Renovate, default rangeStrategy `replace`) rewrote
+      # `>=0.41.0 <0.42.0` to the unbounded-below `<0.47.0`; the lower bound is restored here at the
+      # chart that was live when it merged (0.46.0). renovate.json5 now bumps `>=A <B` ranges as a window,
+      # so the next widen PR proposes `>=0.47.x <0.48.0` rather than `<0.48.0`.
+      version: ">=0.46.0 <0.47.0"
       sourceRef:
         kind: HelmRepository
         name: headlamp