feat: add plan workflow

- update makefile to enable kubernetes auth or roleid auth
- add plan workflow
- update all policies to allow the terraform-vault kubernetes role

.woodpecker/plan.yaml

@@ -0,0 +1,21 @@
+when:
+  - event: pull_request
+
+steps:
+  - name: plan
+    image: git.unkin.net/unkin/almalinux9-opentofu:20260308
+    environment:
+      VAULT_AUTH_METHOD: kubernetes
+    commands:
+      - dnf install vault -y
+      - make plan
+    backend_options:
+      kubernetes:
+        serviceAccountName: terraform-vault
+        resources:
+          requests:
+            memory: 512Mi
+            cpu: 1
+          limits:
+            memory: 2Gi
+            cpu: 2

.woodpecker/pre-commit.yaml

@@ -6,3 +6,13 @@ steps:
     image: git.unkin.net/unkin/almalinux9-opentofu:20260308
     commands:
       - uvx pre-commit run --all-files
+    backend_options:
+      kubernetes:
+        serviceAccountName: default
+        resources:
+          requests:
+            memory: 512Mi
+            cpu: 1
+          limits:
+            memory: 2Gi
+            cpu: 2