🤖 fix: add CoderTemplate.spec.files to aggregated OpenAPI (#81)

## Summary
Expose `CoderTemplate.spec.files` in the aggregated API server OpenAPI
schema so server-side apply (SSA) can manage template source updates.

## Background
SSA relies on the server’s OpenAPI schema/type info. The aggregated API
server’s manually-built OpenAPI definition for `CoderTemplate` omitted
`spec.files`, which prevents apply from properly managing that field.

## Implementation
- Added `spec.files` to the `CoderTemplate` OpenAPI schema as a typed
map (`type: object` + `additionalProperties: { type: string }`).
- Marked the map as `x-kubernetes-map-type: atomic` to avoid per-file
ownership churn in managedFields.
- Added a unit test to assert `spec.files` is present and correctly
typed in OpenAPI.

## Validation
- `make test`
- `make build`
- `make verify-vendor`
- `make lint`

## Risks
Low. This only changes the OpenAPI schema served by the aggregated API
server and adds coverage.

---

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Cost: `$4.71`_

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Author: ibetitsmike

internal/app/apiserverapp/apiserverapp.go

@@ -349,6 +349,20 @@ func getOpenAPIDefinitions(_ openapicommon.ReferenceCallback) map[string]openapi
 	dateTimeSchema := spec.Schema{SchemaProps: spec.SchemaProps{Type: []string{"string"}, Format: "date-time"}}
 	int64Schema := spec.Schema{SchemaProps: spec.SchemaProps{Type: []string{"integer"}, Format: "int64"}}
 	stringSchema := spec.Schema{SchemaProps: spec.SchemaProps{Type: []string{"string"}}}
+	filesSchema := spec.Schema{
+		VendorExtensible: spec.VendorExtensible{
+			Extensions: spec.Extensions{
+				"x-kubernetes-map-type": "atomic",
+			},
+		},
+		SchemaProps: spec.SchemaProps{
+			Type: []string{"object"},
+			AdditionalProperties: &spec.SchemaOrBool{
+				Allows: true,
+				Schema: &stringSchema,
+			},
+		},
+	}
 
 	workspaceSchema := spec.Schema{
 		SchemaProps: spec.SchemaProps{
@@ -399,6 +413,7 @@ func getOpenAPIDefinitions(_ openapicommon.ReferenceCallback) map[string]openapi
 							"displayName":  stringSchema,
 							"description":  stringSchema,
 							"icon":         stringSchema,
+							"files":        filesSchema,
 							"running":      boolSchema,
 						},
 					},

internal/app/apiserverapp/apiserverapp_test.go

@@ -14,6 +14,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
 	genericoptions "k8s.io/apiserver/pkg/server/options"
+	openapiutil "k8s.io/kube-openapi/pkg/util"
 
 	aggregationv1alpha1 "github.com/coder/coder-k8s/api/aggregation/v1alpha1"
 	coderhelper "github.com/coder/coder-k8s/internal/aggregated/coder"
@@ -39,6 +40,42 @@ func TestNewSchemeRegistersAggregationKinds(t *testing.T) {
 	}
 }
 
+func TestOpenAPIDefinitionsIncludeTemplateFiles(t *testing.T) {
+	t.Helper()
+
+	defs := getOpenAPIDefinitions(nil)
+	templateDefinitionName := openapiutil.GetCanonicalTypeName(&aggregationv1alpha1.CoderTemplate{})
+
+	def, ok := defs[templateDefinitionName]
+	if !ok {
+		t.Fatalf("expected OpenAPI definition for %s", templateDefinitionName)
+	}
+
+	templateSpecSchema, ok := def.Schema.Properties["spec"]
+	if !ok {
+		t.Fatal("expected template schema to include spec")
+	}
+
+	filesSchema, ok := templateSpecSchema.Properties["files"]
+	if !ok {
+		t.Fatal("expected template schema to include spec.files")
+	}
+
+	if got := filesSchema.Type; len(got) != 1 || got[0] != "object" {
+		t.Fatalf("expected spec.files type [object], got %v", got)
+	}
+	if filesSchema.AdditionalProperties == nil || filesSchema.AdditionalProperties.Schema == nil {
+		t.Fatal("expected spec.files additionalProperties schema")
+	}
+	if got := filesSchema.AdditionalProperties.Schema.Type; len(got) != 1 || got[0] != "string" {
+		t.Fatalf("expected spec.files additionalProperties type [string], got %v", got)
+	}
+
+	if got, ok := filesSchema.Extensions["x-kubernetes-map-type"]; !ok || got != "atomic" {
+		t.Fatalf("expected spec.files x-kubernetes-map-type atomic, got %v", got)
+	}
+}
+
 func TestInstallAPIGroupRegistersDiscovery(t *testing.T) {
 	t.Helper()