feat(workspaces): Win8 Start-style tile-grid home page

Rebuild the workspace home as a Windows 8 Start-screen-style tile grid,
replacing the max-w-3xl vertical card list.

Pure core (zero DOM/Svelte/fetch, fully unit-tested):
- logic/tile-layout.ts — geometryFor(width, height) resolves WIDE (4 fixed
  ~120px rows, column-wise flow, 4x2 span cap) or TALL (2 fixed columns,
  row-wise flow, 2x2 cap); pack() is the ONLY order->coordinates transform
  (greedy first-fit in fill order, hole-free, render-clamped per geometry);
  firstEmptySlot/insertAtFirstEmptySlot/mergeLayout/resizeTile/moveTile/
  sortByRecentActivity/sanitizeLayout. Persisted data is
  orientation-independent {version:1, tiles:[{id,colSpan,rowSpan,order}]} —
  order + spans only, never positions; the same data renders in either
  geometry (spans clamp for the render, persisted values untouched).
- logic/drag-controller.ts — pure pointer/press state machine: mouse
  threshold-drag + tap-open; touch long-press lifts + selects, pre-lift
  movement cancels so vertical scrolling never fights the gesture.

Shell:
- tile-layout-store.svelte.ts — thin reactive wrapper persisting through
  the injected createLocalStore adapter (dispatch.workspaces.tiles), ops:
  sync/resize/move/placeFirstEmpty/sortByRecentActivity.
- ui/HomeTileGrid.svelte — CSS-grid tile canvas (wide: horizontal scroll +
  snap + wheel pan + pan arrow + scroll indicator; tall: native vertical
  scroll), FLIP-animated reflow, drag ghost, transient resize preview.
- ui/HomeHeader.svelte — fixed chrome: Dispatch display title, New
  workspace popover (same slug validation; creates via create-on-miss and
  does NOT navigate — the new tile lands in the first empty slot in fill
  order and enters rename mode), global Plugins button, sort-by-recent
  overflow; compact icon buttons + bottom sheet on tall screens.
- ui/WorkspaceTile.svelte — tile face (title, /slug, conversation count,
  relative last-activity, live active dots, starred tint); inline rename
  with the old card's semantics.
- ui/TileActionBar.svelte — slides up on select (right-click / long-press):
  Open, Rename, Resize, Star/Unstar, Details, Plugins, Delete (old confirm
  + store call preserved).
- ui/ResizePicker.svelte — Word-style insert-table hover grid (wide 4x2 /
  tall 2x2) with arrow/Enter/Escape support and ghost preview on commit.
- ui/WorkspaceDetails.svelte — flyout holding the old card's default-cwd
  input + default-computer select (same store calls + error states).
- WorkspacesHome.svelte orchestrates; App.svelte untouched (same props).
- WorkspaceCard.svelte is removed (replaced by the tile system).

Manual tile order rules; starred workspaces get a tint (star is no longer
a sort key); workspaces unknown to the layout append at the end.

vitest: jsdom gains PointerEvent (MouseEvent-based) + Element.animate
stubs — the pointer logic is the outermost edge for the drag tests.

Verification: svelte-check 0/0, vitest 1655 passed (102 files, twice),
biome clean, vite build OK.

1 files changed, 0 insertions, 305 deletions

diff --git a/src/features/workspaces/ui/WorkspaceCard.test.ts b/src/features/workspaces/ui/WorkspaceCard.test.ts
deleted file mode 100644
index 72f4e60..0000000
--- a/src/features/workspaces/ui/WorkspaceCard.test.ts
+++ /dev/null
@@ -1,305 +0,0 @@
-import type { WorkspaceEntry } from "@dispatch/wire";
-import { render, screen } from "@testing-library/svelte";
-import userEvent from "@testing-library/user-event";
-import { describe, expect, it, vi } from "vitest";
-import type { WorkspaceResult } from "../adapter/http";
-import type { WorkspaceStore } from "../store.svelte";
-import WorkspaceCard from "./WorkspaceCard.svelte";
-
-function fakeEntry(overrides: Partial<WorkspaceEntry> = {}): WorkspaceEntry {
-  return {
-    id: "my-ws",
-    title: "My Workspace",
-    defaultCwd: null,
-    defaultComputerId: null,
-    starred: false,
-    createdAt: 1,
-    lastActivityAt: 2,
-    conversationCount: 3,
-    ...overrides,
-  };
-}
-
-/** A fake store that records calls + resolves ok. */
-function fakeStore() {
-  return {
-    rename: vi.fn(
-      async (id: string, _title: string): Promise<WorkspaceResult<WorkspaceEntry>> => ({
-        ok: true,
-        value: fakeEntry({ id, title: _title }),
-      }),
-    ),
-    setDefaultCwd: vi.fn(
-      async (id: string, defaultCwd: string | null): Promise<WorkspaceResult<WorkspaceEntry>> => ({
-        ok: true,
-        value: fakeEntry({ id, defaultCwd }),
-      }),
-    ),
-    setDefaultComputer: vi.fn(
-      async (id: string, computerId: string | null): Promise<WorkspaceResult<WorkspaceEntry>> => ({
-        ok: true,
-        value: fakeEntry({ id, defaultComputerId: computerId }),
-      }),
-    ),
-    setStarred: vi.fn(
-      async (id: string, starred: boolean): Promise<WorkspaceResult<WorkspaceEntry>> => ({
-        ok: true,
-        value: fakeEntry({ id, starred }),
-      }),
-    ),
-    remove: vi.fn(
-      async (): Promise<WorkspaceResult<{ closedCount: number }>> => ({
-        ok: true,
-        value: { closedCount: 0 },
-      }),
-    ),
-  };
-}
-
-describe("WorkspaceCard", () => {
-  it("renders the title, slug, and an Open link", () => {
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry(), store, onNavigate: vi.fn(), computers: [] },
-    });
-    expect(screen.getByText("My Workspace")).toBeInTheDocument();
-    expect(screen.getByText("/my-ws")).toBeInTheDocument();
-    expect(screen.getByRole("link", { name: "Open" })).toHaveAttribute("href", "/my-ws");
-  });
-
-  it("double-clicking the title reveals an edit input", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry(), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    await user.dblClick(screen.getByText("My Workspace"));
-    expect(screen.getByLabelText("Workspace title")).toHaveValue("My Workspace");
-  });
-
-  it("renames via the store on Enter", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry(), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    await user.dblClick(screen.getByText("My Workspace"));
-    const input = screen.getByLabelText("Workspace title");
-    await user.clear(input);
-    await user.type(input, "Renamed{Enter}");
-
-    expect(store.rename).toHaveBeenCalledWith("my-ws", "Renamed");
-  });
-
-  it("enables Set only when the cwd differs, then saves it", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ defaultCwd: "/old" }), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    const input = screen.getByLabelText("Default working directory");
-    expect(input).toHaveValue("/old");
-    expect(screen.getByRole("button", { name: "Set" })).toBeDisabled();
-
-    await user.clear(input);
-    await user.type(input, "/new/path");
-    expect(screen.getByRole("button", { name: "Set" })).toBeEnabled();
-
-    await user.click(screen.getByRole("button", { name: "Set" }));
-    expect(store.setDefaultCwd).toHaveBeenCalledWith("my-ws", "/new/path");
-  });
-
-  it("clears the cwd to null when saved empty (inherits the server default)", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ defaultCwd: "/old" }), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    const input = screen.getByLabelText("Default working directory");
-    await user.clear(input);
-    await user.click(screen.getByRole("button", { name: "Set" }));
-
-    expect(store.setDefaultCwd).toHaveBeenCalledWith("my-ws", null);
-  });
-
-  it("the Open link navigates to the workspace in the same tab (SPA navigation, no new tab)", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    const onNavigate = vi.fn();
-    render(WorkspaceCard, { props: { ws: fakeEntry(), store, onNavigate, computers: [] } });
-
-    const open = screen.getByRole("link", { name: "Open" });
-    // Still a real link (progressive enhancement): href points at the workspace.
-    expect(open).toHaveAttribute("href", "/my-ws");
-    // But it no longer opens a new browser tab.
-    expect(open).not.toHaveAttribute("target", "_blank");
-    // Clicking navigates in-place via the SPA callback.
-    await user.click(open);
-    expect(onNavigate).toHaveBeenCalledTimes(1);
-    expect(onNavigate).toHaveBeenCalledWith("/my-ws");
-  });
-
-  // ── Active indicator (loading dots) ──────────────────────────────────────
-
-  it("shows no loading-dots when no hasActive port is given", () => {
-    const store = fakeStore() as unknown as WorkspaceStore;
-    const { container } = render(WorkspaceCard, {
-      props: { ws: fakeEntry(), store, onNavigate: vi.fn(), computers: [] },
-    });
-    expect(container.querySelector(".loading-dots")).toBeNull();
-  });
-
-  it("shows no loading-dots when hasActive returns false", () => {
-    const store = fakeStore() as unknown as WorkspaceStore;
-    const { container } = render(WorkspaceCard, {
-      props: {
-        ws: fakeEntry(),
-        store,
-        onNavigate: vi.fn(),
-        computers: [],
-        hasActive: () => false,
-      },
-    });
-    expect(container.querySelector(".loading-dots")).toBeNull();
-  });
-
-  it("shows loading-dots when hasActive returns true", () => {
-    const store = fakeStore() as unknown as WorkspaceStore;
-    const { container } = render(WorkspaceCard, {
-      props: {
-        ws: fakeEntry(),
-        store,
-        onNavigate: vi.fn(),
-        computers: [],
-        hasActive: () => true,
-      },
-    });
-    const dots = container.querySelector(".loading-dots");
-    expect(dots).not.toBeNull();
-    // Accessible label ties the indicator to the workspace-active concept.
-    expect(dots?.getAttribute("aria-label")).toBe("Workspace has active conversations");
-  });
-
-  it("forwards the workspace id to hasActive", () => {
-    const store = fakeStore() as unknown as WorkspaceStore;
-    const seen: string[] = [];
-    render(WorkspaceCard, {
-      props: {
-        ws: fakeEntry({ id: "proj-x" }),
-        store,
-        onNavigate: vi.fn(),
-        computers: [],
-        hasActive: (id: string) => {
-          seen.push(id);
-          return false;
-        },
-      },
-    });
-    expect(seen).toEqual(["proj-x"]);
-  });
-
-  it("renders an outline star button for an unstarred workspace", () => {
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ starred: false }), store, onNavigate: vi.fn(), computers: [] },
-    });
-    const star = screen.getByRole("button", { name: "Star workspace" });
-    expect(star).toHaveAttribute("aria-pressed", "false");
-  });
-
-  it("renders a filled star button for a starred workspace", () => {
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ starred: true }), store, onNavigate: vi.fn(), computers: [] },
-    });
-    const star = screen.getByRole("button", { name: "Unstar workspace" });
-    expect(star).toHaveAttribute("aria-pressed", "true");
-  });
-
-  it("toggles the star via the store on click", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ starred: false }), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    await user.click(screen.getByRole("button", { name: "Star workspace" }));
-    expect(store.setStarred).toHaveBeenCalledWith("my-ws", true);
-  });
-
-  it("clicking a starred workspace's star calls setStarred(id, false)", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ starred: true }), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    await user.click(screen.getByRole("button", { name: "Unstar workspace" }));
-    expect(store.setStarred).toHaveBeenCalledWith("my-ws", false);
-  });
-
-  it("renders no star error on a successful toggle", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ starred: false }), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    await user.click(screen.getByRole("button", { name: "Star workspace" }));
-    expect(screen.queryByText(/Star toggle failed/i)).not.toBeInTheDocument();
-  });
-
-  it("shows an inline error when setStarred fails (result.ok false)", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    // The store reverts the optimistic flip on failure, so the entry's
-    // `starred` stays false — fake the revert by returning ok:false unchanged.
-    store.setStarred = vi.fn(
-      async (): Promise<WorkspaceResult<WorkspaceEntry>> => ({ ok: false, error: "boom" }),
-    );
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ starred: false }), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    await user.click(screen.getByRole("button", { name: "Star workspace" }));
-
-    expect(screen.getByText("boom")).toBeInTheDocument();
-  });
-
-  it("re-enables the star button after a failure (savingStar resets)", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    store.setStarred = vi.fn(
-      async (): Promise<WorkspaceResult<WorkspaceEntry>> => ({ ok: false, error: "boom" }),
-    );
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ starred: false }), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    const star = screen.getByRole("button", { name: "Star workspace" });
-    await user.click(star);
-    // After the failed toggle, the button is NOT disabled (savingStar reset).
-    expect(star).not.toBeDisabled();
-  });
-
-  it("re-enables the star button even when setStarred throws", async () => {
-    const user = userEvent.setup();
-    const store = fakeStore() as unknown as WorkspaceStore;
-    store.setStarred = vi.fn(async (): Promise<WorkspaceResult<WorkspaceEntry>> => {
-      throw new Error("network");
-    });
-    render(WorkspaceCard, {
-      props: { ws: fakeEntry({ starred: false }), store, onNavigate: vi.fn(), computers: [] },
-    });
-
-    const star = screen.getByRole("button", { name: "Star workspace" });
-    await user.click(star);
-    // savingStar must reset via try/finally even on a throw.
-    expect(star).not.toBeDisabled();
-    expect(screen.getByText("network")).toBeInTheDocument();
-  });
-});