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

The top-level `strategy` value only ever configured the update strategy of the Gitea Deployment, but had its own
`## @section strategy` next to chart-wide settings. Moving it into the `deployment` dict completes the
consolidation already done for `affinity`, `dnsConfig`, `nodeSelector`, `priorityClassName`, `resources`,
`schedulerName`, `tolerations` and `topologySpreadConstraints`, so everything that shapes the Deployment now
lives in one predictable place.

The parameter descriptions were rewritten while moving them. `strategy type`, `maxSurge` and `maxUnavailable`
merely repeated the key names and gave readers of the generated parameter table no information at all. They now
state the accepted values and that `rollingUpdate` is ignored for the `Recreate` strategy.

Since the `strategy` section disappeared and `clusterDomain` moved into a new `Network` section, the manually
maintained table of contents was updated accordingly, otherwise `markdownlint` fails with MD051 on the dangling
link fragments.

A deprecation check fails the release when the removed top-level value is still set. Silently ignoring it would
be risky: a `Recreate` strategy configured to avoid two pods writing to the same `ReadWriteOnce` volume would
fall back to `RollingUpdate` without any warning.

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

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

unittests/helm/deployment/basic.yaml

@@ -152,6 +152,25 @@ tests:
       - equal:
           path: spec.template.spec.schedulerName
           value: stork
+  - it: strategy defaults to a rolling update
+    template: templates/gitea/deployment.yaml
+    asserts:
+      - equal:
+          path: spec.strategy
+          value:
+            type: RollingUpdate
+            rollingUpdate:
+              maxUnavailable: 0
+              maxSurge: 100%
+  - it: strategy omits rollingUpdate for other strategy types
+    template: templates/gitea/deployment.yaml
+    set:
+      deployment.strategy.type: Recreate
+    asserts:
+      - equal:
+          path: spec.strategy
+          value:
+            type: Recreate
   - it: tolerations are undefined
     template: templates/gitea/deployment.yaml
     asserts:

unittests/helm/deployment/deprecations.yaml

@@ -66,6 +66,13 @@ tests:
     asserts:
       - failedTemplate:
           errorMessage: "`schedulerName` does no longer exist. Please refer to the changelog and configure `deployment.schedulerName` instead."
+  - it: fails when the removed `strategy` value is set
+    set:
+      strategy:
+        type: Recreate
+    asserts:
+      - failedTemplate:
+          errorMessage: "`strategy` does no longer exist. Please refer to the changelog and configure `deployment.strategy` instead."
   - it: fails when the removed `tolerations` value is set
     set:
       tolerations:
@@ -101,6 +108,8 @@ tests:
         limits:
           cpu: 100m
       schedulerName: stork
+      strategy:
+        type: Recreate
       tolerations:
         - key: database/type
           operator: Equal