fix(project): exempt cdn_channel consumers from released-source validation; review polish

- Extend ValidateLayout exemption so cdn_channel consumers skip root/include/
  derive/manifest requirements (they resolve entirely from Source.* at runtime).
- Add TestValidateLayoutAcceptsCDNChannelConsumerWithoutReleasedSourceFields.
- Fix inverted precedence comment in CDN-base resolution block (autogen.go:325).
- Add broken-YAML subtest to TestResolveCDNChannelHardFail.
- Add assumption comment to autogenConsumerManagedLockKeyMatcher re folder_name+preserve.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/topdata/autogen_cdn_channel_test.go

@@ -159,6 +159,18 @@ func TestResolveCDNChannelHardFail(t *testing.T) {
 			t.Fatalf("want HARD fail, got %v", err)
 		}
 	})
+
+	t.Run("malformed vfxs.yml: syntactically broken YAML", func(t *testing.T) {
+		srv := cdnServer(t, map[string]string{
+			"/releases/haks/channels.json": `{"current":"v1"}`,
+			"/releases/haks/v1/vfxs.yml":   "assets:\n  - path: [unterminated",
+		})
+		t.Setenv("BUNNY_CDN_BASE", srv.URL)
+		_, err := resolveCDNChannelManifest(testProject(root), c, c.Source, nil)
+		if err == nil || errorIsUnavailable(err) {
+			t.Fatalf("want HARD fail on broken YAML, got %v", err)
+		}
+	})
 }
 
 func TestResolveCDNChannelOfflineOverride(t *testing.T) {