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

Moving `affinity` into the `deployment` dict groups it with the other Deployment-specific values and prepares a
consistent structure for further migrations of pod-level settings.

A deprecation check is added so that existing installations fail fast with an actionable error message instead of
silently dropping the affinity rules, which would otherwise lead to pods being scheduled on unintended nodes.

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

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

values.yaml

@@ -319,9 +319,6 @@ nodeSelector: {}
 ## @param tolerations Tolerations for the deployment
 tolerations: []
 
-## @param affinity Affinity for the deployment
-affinity: {}
-
 ## @param topologySpreadConstraints TopologySpreadConstraints for the deployment
 topologySpreadConstraints: []
 
@@ -331,11 +328,30 @@ dnsConfig: {}
 ## @param priorityClassName priorityClassName for the deployment
 priorityClassName: ""
 
-## @param deployment.env  Additional environment variables to pass to containers
+## @param deployment.affinity Affinity for the deployment.
+## @param deployment.env Additional environment variables to pass to containers
 ## @param deployment.terminationGracePeriodSeconds How long to wait until forcefully kill the pod
 ## @param deployment.labels Labels for the deployment
 ## @param deployment.annotations Annotations for the Gitea deployment to be created
 deployment:
+  affinity: {}
+    # nodeAffinity:
+    #   requiredDuringSchedulingIgnoredDuringExecution:
+    #     nodeSelectorTerms:
+    #     - matchExpressions:
+    #       - key: kubernetes.io/os
+    #         operator: In
+    #         values:
+    #         - linux
+    #   preferredDuringSchedulingIgnoredDuringExecution:
+    #   - weight: 20
+    #     preference:
+    #       matchExpressions:
+    #       - key: kubernetes.io/arch
+    #         operator: In
+    #         values:
+    #         - amd64
+
   env: []
   # - name: VARIABLE
   #   value: my-value
@@ -370,7 +386,7 @@ secrets:
     ## @param secrets.admin.new.annotations Annotations for the admin Secret
     ## @param secrets.admin.new.labels Labels for the admin Secret
     ## @param secrets.admin.new.email Email of the Gitea admin user
-    ## @param secrets.admin.new.password Password of the Gitea admin user
+    ## @param secrets.admin.new.password Password of the Gitea admin user.
     ## @param secrets.admin.new.username Username of the Gitea admin user
     new:
       annotations: {}