feat(deployment)!: move schedulerName to deployment.schedulerName

The top-level `schedulerName` value only ever configured the pod spec of the Gitea Deployment, but was declared
next to chart-wide settings. Moving it into the `deployment` dict completes the consolidation already done for
`affinity`, `dnsConfig`, `nodeSelector`, `priorityClassName`, `resources`, `tolerations` and
`topologySpreadConstraints`, so every pod scheduling setting now lives in one predictable place.

A deprecation check fails the release when the removed top-level value is still set. Silently ignoring it would
be hard to debug: the pod would fall back to the `default-scheduler` without any warning, bypassing the custom
scheduler the user relies on for placement decisions such as storage locality.

BREAKING CHANGE: `schedulerName` no longer exists. Use `deployment.schedulerName` instead. Installations that
still set `schedulerName` will fail unless `checkDeprecation` is set to `false`.

Co-authored-by: Copilot <copilot@github.com>

templates/gitea/deprecation.yaml

@@ -70,6 +70,11 @@
     {{- fail "`resources` does no longer exist. Please refer to the changelog and configure `deployment.gitea.resources` instead." -}}
   {{- end -}}
 
+  {{/* SCHEDULER NAME */}}
+  {{- if .Values.schedulerName -}}
+    {{- fail "`schedulerName` does no longer exist. Please refer to the changelog and configure `deployment.schedulerName` instead." -}}
+  {{- end -}}
+
   {{/* TOLERATIONS */}}
   {{- if .Values.tolerations -}}
     {{- fail "`tolerations` does no longer exist. Please refer to the changelog and configure `deployment.tolerations` instead." -}}