fix(review-1.3): render home tiles before layout revalidation

2 files changed, 118 insertions, 4 deletions

diff --git a/src/features/workspaces/ui/WorkspacesHome.svelte b/src/features/workspaces/ui/WorkspacesHome.svelte
index 65e1593..196e831 100644
--- a/src/features/workspaces/ui/WorkspacesHome.svelte
+++ b/src/features/workspaces/ui/WorkspacesHome.svelte
@@ -12,6 +12,7 @@
   import {
     DEFAULT_VIEWPORT,
     geometryFor,
+    mergeLayout,
     pack,
     type GridGeometry,
     type Span,
@@ -86,11 +87,15 @@
   });
 
   // ── The tile canvas' size decides the geometry (ONE pure function — no
-  // breakpoint classes). Unmeasured (tests) → the default landscape viewport.
+  // breakpoint classes). Start from the viewport, matching the boot probe;
+  // the canvas measurement then refines it (no transient wide reset on phones).
+  const initialViewport = typeof window === "undefined"
+    ? DEFAULT_VIEWPORT
+    : { width: window.innerWidth, height: window.innerHeight };
   let regionEl = $state<HTMLDivElement | undefined>();
   let size = $state<{ width: number; height: number } | undefined>();
   const geometry: GridGeometry = $derived(
-    geometryFor(size?.width ?? DEFAULT_VIEWPORT.width, size?.height ?? DEFAULT_VIEWPORT.height),
+    geometryFor(size?.width ?? initialViewport.width, size?.height ?? initialViewport.height),
   );
 
   $effect(() => {
@@ -115,7 +120,12 @@
 
   // The grid view: the SAME persisted data packs into either geometry —
   // positions re-derive here, spans clamp for the RENDER only.
-  const placements = $derived(pack(tiles.entries, geometry));
+  // Render-only fallback: workspace discovery must not wait for layout GET.
+  // Never sync/commit this provisional arrangement while the probe is unknown.
+  const entries = $derived(tiles.entries.length > 0
+    ? tiles.entries
+    : mergeLayout(null, store.list.map((ws) => ws.id)));
+  const placements = $derived(pack(entries, geometry));
   const workspacesById = $derived(new Map(store.list.map((ws) => [ws.id, ws])));
 
   // ── Selection + action bar ─────────────────────────────────────────────────
diff --git a/src/features/workspaces/ui/WorkspacesHome.test.ts b/src/features/workspaces/ui/WorkspacesHome.test.ts
index d4316b1..5a66a42 100644
--- a/src/features/workspaces/ui/WorkspacesHome.test.ts
+++ b/src/features/workspaces/ui/WorkspacesHome.test.ts
@@ -4,7 +4,7 @@ import { render, screen, waitFor } from "@testing-library/svelte";
 import userEvent from "@testing-library/user-event";
 import { describe, expect, it, vi } from "vitest";
 import type { WorkspaceHttp, WorkspaceResult } from "../adapter/http";
-import type { TileLayoutHttp } from "../adapter/tile-layout-http";
+import type { TileLayoutHttp, TileLayoutHttpResult } from "../adapter/tile-layout-http";
 import type { WorkspaceLookup } from "../logic/create";
 import { createTileLayoutStore } from "../tile-layout-store.svelte";
 import WorkspacesHome from "./WorkspacesHome.svelte";
@@ -101,6 +101,110 @@ describe("WorkspacesHome (tile canvas)", () => {
     expect([...wrappers].map((el) => el.getAttribute("data-tile-id"))).toEqual(["b", "a"]);
   });
 
+  it.each([
+    false,
+    true,
+  ])("renders before the layout probe resolves (cached: %s)", async (cached) => {
+    const layout = memoryLayout();
+    const gate: { release?: (result: TileLayoutHttpResult) => void } = {};
+    layout.getLayout = vi.fn(
+      () =>
+        new Promise<TileLayoutHttpResult>((resolve) => {
+          gate.release = resolve;
+        }),
+    );
+    const put = vi.spyOn(layout, "putLayout");
+    const stored = {
+      version: 2,
+      tiles: [
+        { id: "b", order: 0, colSpan: 2, rowSpan: 2 },
+        { id: "a", order: 1, colSpan: 1, rowSpan: 1 },
+      ],
+    };
+    const storage = cached ? localStorage : undefined;
+    storage?.setItem("dispatch.tile-layout.tall", JSON.stringify(stored));
+    const width = vi.spyOn(window, "innerWidth", "get").mockReturnValue(390);
+    const height = vi.spyOn(window, "innerHeight", "get").mockReturnValue(844);
+    const tiles = createTileLayoutStore({ http: layout, initialMode: "tall", storage });
+    try {
+      render(WorkspacesHome, {
+        props: {
+          store: (await import("../store.svelte")).createWorkspaceStore(
+            fakeHttp([ws(), ws({ id: "b", title: "B" })]),
+          ),
+          onNavigate: vi.fn(),
+          computers: [],
+          tiles,
+        },
+      });
+      await screen.findByRole("button", { name: "Open workspace A" });
+      await screen.findByRole("button", { name: "Open workspace B" });
+      expect(
+        [...document.querySelectorAll("[data-tile-id]")].map((el) =>
+          el.getAttribute("data-tile-id"),
+        ),
+      ).toEqual(cached ? ["b", "a"] : ["a", "b"]);
+      expect(tiles.providerState).toBe("unknown");
+      expect(tiles.entries).toEqual(cached ? stored.tiles : []);
+      expect(layout.getLayout).toHaveBeenCalledExactlyOnceWith("tall");
+      expect(put).not.toHaveBeenCalled();
+      gate.release?.({
+        ok: true,
+        layout: {
+          version: 2,
+          tiles: stored.tiles
+            .slice()
+            .reverse()
+            .map((tile, order) => ({ ...tile, order })),
+        },
+      });
+      await waitFor(() => {
+        expect(tiles.providerState).toBe("present");
+        expect(tiles.entries.map((tile) => tile.id)).toEqual(["a", "b"]);
+        // CSS-grid coordinates determine visual order; keyed DOM nodes may stay put.
+        expect(document.querySelector('[data-tile-id="a"]')).toHaveStyle("grid-row: 1 / span 1");
+        expect(document.querySelector('[data-tile-id="b"]')).toHaveStyle("grid-row: 2 / span 2");
+      });
+    } finally {
+      width.mockRestore();
+      height.mockRestore();
+      storage?.removeItem("dispatch.tile-layout.tall");
+    }
+  });
+
+  it("re-probes when the canvas changes orientation", async () => {
+    let measure: ResizeObserverCallback = () => {};
+    const observer = vi.spyOn(globalThis, "ResizeObserver").mockImplementation((callback) => {
+      measure = callback;
+      return { observe() {}, unobserve() {}, disconnect() {} };
+    });
+    const layout = memoryLayout();
+    const get = vi.spyOn(layout, "getLayout");
+    const tiles = createTileLayoutStore({ http: layout });
+    try {
+      render(WorkspacesHome, {
+        props: {
+          store: (await import("../store.svelte")).createWorkspaceStore(fakeHttp()),
+          onNavigate: vi.fn(),
+          computers: [],
+          tiles,
+        },
+      });
+      await screen.findByRole("button", { name: "Open workspace A" });
+      measure(
+        [{ contentRect: { width: 390, height: 700 } }] as ResizeObserverEntry[],
+        {} as ResizeObserver,
+      );
+      await waitFor(() => {
+        expect(tiles.mode).toBe("tall");
+        expect(get.mock.calls).toEqual([["wide"], ["tall"]]);
+      });
+      await screen.findByRole("button", { name: "Open workspace A" });
+    } finally {
+      observer.mockRestore();
+    }
+  });
+
   it("clicking a tile navigates to the workspace path", async () => {
     const user = userEvent.setup();
     const onNavigate = vi.fn();