ui(deploy): loading-aware default for dirty-state baseline

Previously `dirtyState?.dirty ?? true` caused a stale `Redeploy` label
to flash briefly while the first fetch was in flight. Gate the default
on isLoading so the button starts as `Save (disabled)` until the
endpoint resolves — spurious Redeploy clicks were harmless but the
loading-state UX was wrong.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/src/pages/AppsTab/AppDeploymentPage/index.tsx

@@ -62,7 +62,7 @@ export default function AppDeploymentPage() {
   const activeDeployment = deployments.find((d) => d.status === 'STARTING') ?? null;
 
   const { data: agentConfig = null } = useApplicationConfig(app?.slug, selectedEnv);
-  const { data: dirtyState } = useDirtyState(selectedEnv, app?.slug);
+  const { data: dirtyState, isLoading: dirtyLoading } = useDirtyState(selectedEnv, app?.slug);
 
   // Mutations
   const createApp = useCreateApp();
@@ -113,7 +113,11 @@ export default function AppDeploymentPage() {
   const dirty = useFormDirty(form, serverState, stagedJar);
   const { dialogOpen: blockerOpen, confirm: blockerConfirm, cancel: blockerCancel } =
     useUnsavedChangesBlocker(dirty.anyLocalEdit);
-  const serverDirtyAgainstDeploy = dirtyState?.dirty ?? true;
+  // Before the first dirty-state fetch resolves, default to "not dirty" so the
+  // primary button shows `Save (disabled)` — not a stale `Redeploy`. Once loaded,
+  // fall back to `true` if the endpoint failed entirely (fail-safe for the
+  // redeploy path).
+  const serverDirtyAgainstDeploy = app && dirtyLoading ? false : (dirtyState?.dirty ?? true);
   const deploymentInProgress = !!activeDeployment;
   const primaryMode = computeMode({
     deploymentInProgress,