refactor(run): drop the lane progress bar, iconify pane layout, and one-row the run setup

Four more spots that spent height saying what was already visible or
saying too much of it.

**LaneCard** drops the progress bar and percent entirely — the pipeline
map right below the card already draws the same number as named,
coloured nodes, and a bar beside it was a worse second telling of it.

**SplitLayoutToggle** (Workspace) swaps "1 pane" / "2 pane" / "4 pane"
text buttons for the conventional square / two-column / 2x2-grid icons
(`Square`, `Columns2`, `Grid2x2`) most apps use for this. The words move
to `aria-label` and `title` rather than disappearing.

**RunSetup** merges the fresh/resume source picker onto the same row as
the Working directory / Model / Permission mode / Thinking effort fields
instead of a second row above them — settings left, New/Resume session
right. The session picker for an active resume still gets its own row
below, since it only appears in that one state.

**LaneConsolePane**'s "Run Claude" header goes from a two-row title +
wrapped blurb to one row (smaller icon and title), and the blurb itself
is trimmed to one short sentence, hidden below `sm` where it would wrap
again anyway.

`docs/LANES.md` updated to match (split-view description, lane-card
field list, and `agenthub stage`'s progress-bar wording).

Verification: `tsc --noEmit` clean, `npx vitest run` 508/508 (2 stale
progress-bar assertions in LaneCard.test.tsx replaced with one asserting
the bar is gone), `npm run build` clean, screens.snapshot diff reviewed
before regenerating (icon buttons + new blurb + reordered DOM only), file
headers audit clean.

client/src/components/lanes/__tests__/LaneCard.test.tsx

@@ -155,14 +155,12 @@ describe("LaneCard rebuilt layout", () => {
     expect(screen.getByTestId("lane-card-7")).toBeInTheDocument();
   });
 
-  it("shows the progress percentage", () => {
+  // The pipeline map below this card draws the same progress as named nodes,
+  // so the card no longer repeats it as a bar and a percent.
+  it("leaves progress to the pipeline map rather than drawing its own bar", () => {
     render(<LaneCard lane={full()} onAction={vi.fn()} />);
-    expect(screen.getByText("48%")).toBeInTheDocument();
-  });
-
-  it("gives the progress bar a width matching the lane's progress", () => {
-    render(<LaneCard lane={full()} onAction={vi.fn()} />);
-    expect(screen.getByTestId("lane-progress-fill").getAttribute("style")).toContain("48%");
+    expect(screen.queryByTestId("lane-progress-fill")).toBeNull();
+    expect(screen.queryByText("48%")).toBeNull();
   });
 
   it("surfaces a needs-you message", () => {