Recreate deleted worktrees from their branch on restore

Archiving a Paseo-owned worktree deletes its directory, so reopening its
agent previously dead-ended even after the workspace record came back —
there was no folder to return to.

Restore now recreates the worktree at its original path from the kept
branch (the branch is never deleted on archive), re-points the same
workspace record, and clears archivedAt — preserving the workspaceId so
the agent stays linked. The directory is recreated before the un-archive
so the reconciler can't re-archive it for a missing directory. A deleted
or already-checked-out branch surfaces a typed failure and leaves the
workspace archived.

Gated behind a worktreeRestore capability flag; older hosts get an
explicit "update your host" state instead of a misleading failure.

packages/app/src/screens/workspace/workspace-route-state-views.tsx

@@ -23,6 +23,14 @@ export function renderWorkspaceRouteGate(input: {
       return <WorkspaceConnecting hostName={input.state.hostName} />;
     case "restoring":
       return <WorkspaceRestoring hostName={input.state.hostName} />;
+    case "needsHostUpgrade":
+      return (
+        <WorkspaceEmptyState
+          titleKey="workspace.route.needsHostUpgrade"
+          hostName={input.state.hostName}
+          onDismiss={input.actions.onDismissMissingWorkspace}
+        />
+      );
     case "unreachable":
       return (
         <WorkspaceUnreachable
@@ -33,9 +41,11 @@ export function renderWorkspaceRouteGate(input: {
       );
     case "missing":
       return (
-        <WorkspaceMissing
+        <WorkspaceEmptyState
+          titleKey={
+            input.state.restoreFailed ? "workspace.route.restoreFailed" : "workspace.route.missing"
+          }
           hostName={input.state.hostName}
-          restoreFailed={input.state.restoreFailed}
           onDismiss={input.actions.onDismissMissingWorkspace}
         />
       );
@@ -142,13 +152,16 @@ function WorkspaceUnreachable({
   );
 }
 
-function WorkspaceMissing({
+function WorkspaceEmptyState({
+  titleKey,
   hostName,
-  restoreFailed,
   onDismiss,
 }: {
+  titleKey:
+    | "workspace.route.missing"
+    | "workspace.route.restoreFailed"
+    | "workspace.route.needsHostUpgrade";
   hostName: string;
-  restoreFailed: boolean;
   onDismiss: () => void;
 }) {
   const { t } = useTranslation();
@@ -156,9 +169,7 @@ function WorkspaceMissing({
   return (
     <View style={styles.emptyState}>
       <View style={styles.textStack}>
-        <Text style={styles.title}>
-          {restoreFailed ? t("workspace.route.restoreFailed") : t("workspace.route.missing")}
-        </Text>
+        <Text style={styles.title}>{t(titleKey)}</Text>
         <Text style={styles.description}>{hostName}</Text>
       </View>
       <View style={styles.actions}>

packages/app/src/screens/workspace/workspace-route-state.test.ts

@@ -127,6 +127,19 @@ describe("resolveWorkspaceRouteState", () => {
     ).toEqual({ kind: "restoring", hostName: "Laptop" });
   });
 
+  it("returns needsHostUpgrade when the daemon lacks the restore capability", () => {
+    expect(
+      resolveWorkspaceRouteState({
+        hostName: "Laptop",
+        connectionStatus: "online",
+        lastError: null,
+        workspace: null,
+        hasHydratedWorkspaces: true,
+        restoreStatus: "needs-host-upgrade",
+      }),
+    ).toEqual({ kind: "needsHostUpgrade", hostName: "Laptop" });
+  });
+
   it("falls back to a restore-failed missing state once the restore times out", () => {
     expect(
       resolveWorkspaceRouteState({

packages/app/src/screens/workspace/workspace-route-state.ts

@@ -17,6 +17,7 @@ export type WorkspaceRouteState =
     }
   | { kind: "loading"; hostName: string }
   | { kind: "restoring"; hostName: string }
+  | { kind: "needsHostUpgrade"; hostName: string }
   | { kind: "missing"; hostName: string; restoreFailed: boolean };
 
 export function resolveWorkspaceRouteState(input: {
@@ -25,7 +26,7 @@ export function resolveWorkspaceRouteState(input: {
   lastError: string | null;
   workspace: WorkspaceDescriptor | null;
   hasHydratedWorkspaces: boolean;
-  restoreStatus: "restoring" | "failed" | null;
+  restoreStatus: "restoring" | "failed" | "needs-host-upgrade" | null;
 }): WorkspaceRouteState {
   if (input.workspace) {
     if (input.connectionStatus === "online") {
@@ -45,6 +46,10 @@ export function resolveWorkspaceRouteState(input: {
       return { kind: "restoring", hostName: input.hostName };
     }
 
+    if (input.restoreStatus === "needs-host-upgrade") {
+      return { kind: "needsHostUpgrade", hostName: input.hostName };
+    }
+
     if (input.hasHydratedWorkspaces) {
       return {
         kind: "missing",