Improve startup provider snapshots and dev harness

packages/app/src/screens/workspace/workspace-header-source.ts

@@ -1,5 +1,41 @@
 import type { WorkspaceDescriptor } from "@/stores/session-store";
 
+export type WorkspaceHeaderCheckoutState =
+  | { kind: "pending" }
+  | { kind: "error" }
+  | { kind: "ready"; checkout: { isGit: boolean; currentBranch: string | null } };
+
+type WorkspaceHeaderRenderState =
+  | { kind: "skeleton" }
+  | {
+      kind: "ready";
+      title: string;
+      subtitle: string;
+      shouldShowSubtitle: boolean;
+      isGitCheckout: boolean;
+      currentBranchName: string | null;
+    };
+
+function trimNonEmpty(value: string | null | undefined): string | null {
+  if (typeof value !== "string") {
+    return null;
+  }
+  const trimmed = value.trim();
+  return trimmed.length > 0 ? trimmed : null;
+}
+
+function areHeaderLabelsEquivalent(
+  a: string | null | undefined,
+  b: string | null | undefined,
+): boolean {
+  const normalizedA = trimNonEmpty(a)?.toLocaleLowerCase();
+  const normalizedB = trimNonEmpty(b)?.toLocaleLowerCase();
+  if (!normalizedA || !normalizedB) {
+    return false;
+  }
+  return normalizedA === normalizedB;
+}
+
 export function resolveWorkspaceHeader(input: { workspace: WorkspaceDescriptor }): {
   title: string;
   subtitle: string;
@@ -10,6 +46,35 @@ export function resolveWorkspaceHeader(input: { workspace: WorkspaceDescriptor }
   };
 }
 
+export function resolveWorkspaceHeaderRenderState(input: {
+  workspace: WorkspaceDescriptor | null;
+  checkoutState: WorkspaceHeaderCheckoutState;
+}): WorkspaceHeaderRenderState {
+  if (!input.workspace) {
+    return { kind: "skeleton" };
+  }
+
+  if (input.checkoutState.kind === "pending" && input.workspace.projectKind === "git") {
+    return { kind: "skeleton" };
+  }
+
+  const header = resolveWorkspaceHeader({ workspace: input.workspace });
+  const checkout = input.checkoutState.kind === "ready" ? input.checkoutState.checkout : null;
+  const currentBranchName =
+    checkout?.isGit && checkout.currentBranch !== "HEAD"
+      ? trimNonEmpty(checkout.currentBranch)
+      : null;
+
+  return {
+    kind: "ready",
+    title: header.title,
+    subtitle: header.subtitle,
+    shouldShowSubtitle: !areHeaderLabelsEquivalent(header.title, header.subtitle),
+    isGitCheckout: checkout?.isGit ?? false,
+    currentBranchName,
+  };
+}
+
 export function shouldRenderMissingWorkspaceDescriptor(input: {
   workspace: WorkspaceDescriptor | null;
   hasHydratedWorkspaces: boolean;