feat(lanes): Antigravity lanes, release exited panes, fresh Codex starts

- antigravity: a third lane tool running Antigravity's `agy` CLI. `-i`
  carries the first prompt, `--continue` resumes; `agy` has no model,
  effort or permission flag, and `--dangerously-skip-permissions` is never
  emitted. No pipeline, no agents install, and no AI Router (native only,
  else EUNSUPPORTED). Add lane gains an Antigravity choice and the binary
  probe maps it to `agy`.
- UI: the lane card no longer renders a frame holding only a "Codex" chip,
  and the prompt box names the lane's CLI ("Ask Codex anything…"), via
  LANE_TOOL_LABEL.
- runs: a pane that exits is released on a 10 s server beat
  (healAllRunIds, DASHBOARD_RUN_HEAL_MS). Codex and Antigravity fire no
  hook, so their lanes stayed "running" until something re-read them.
- codex: Start no longer sends resumeLast — only "Resume last session"
  continues the previous thread.

client/src/components/lanes/AddLaneModal.tsx

@@ -429,6 +429,15 @@ export function AddLaneModal({
               label={t("addLaneToolCodex")}
               onClick={() => setTool("codex")}
             />
+            <Seg
+              active={tool === "antigravity"}
+              label={t("addLaneToolAntigravity")}
+              onClick={() => {
+                setTool("antigravity");
+                // `agy` cannot run behind an AI Router (see router-apply.js).
+                setRouter("native");
+              }}
+            />
           </div>
         </div>
 
@@ -635,7 +644,10 @@ export function AddLaneModal({
             hid it. The pipeline picker is gone entirely: every lane is created
             on `default` (the server's own default) and the template is changed
             from the lane's own header afterwards. */}
-        <div className="rounded-md border border-border-light bg-surface-0 p-2">
+        <div
+          className="rounded-md border border-border-light bg-surface-0 p-2"
+          hidden={tool === "antigravity"}
+        >
           <div>
             <fieldset>
               <legend className="mb-1 text-xs text-fg-secondary">{t("addLaneRouterLabel")}</legend>

client/src/components/lanes/LaneCard.tsx

@@ -363,8 +363,8 @@ export function LaneToolsMenu({ lane }: { lane: Lane }) {
           role="menu"
           className="absolute right-0 z-10 mt-1 min-w-44 overflow-hidden rounded-md border border-border-light bg-surface-0 py-1 shadow-lg shadow-black/40"
         >
-          {/* Claude-only: a codex lane has no agents to install. */}
-          {lane.tool !== "codex" && (
+          {/* Claude-only: other CLIs have no agents to install. */}
+          {lane.tool === "claude" && (
             <button
               type="button"
               role="menuitem"
@@ -379,7 +379,7 @@ export function LaneToolsMenu({ lane }: { lane: Lane }) {
               {t("actions.agentsInstall")}
             </button>
           )}
-          {lane.tool !== "codex" && (
+          {lane.tool === "claude" && (
             <button
               type="button"
               role="menuitem"
@@ -487,18 +487,11 @@ export default function LaneCard({
         // renders no frame at all rather than an empty box.
         className="flex flex-col rounded-lg border border-border bg-surface-4 p-2.5 transition-colors hover:border-border-light empty:hidden"
       >
-        {(lane.ci_status || lane.tool === "codex") && (
+        {lane.ci_status && (
           <div className="mb-2 flex flex-wrap items-center gap-1.5 text-[11px]">
-            {lane.ci_status && (
-              <span className="rounded bg-surface-2 px-1.5 py-0.5 text-fg-secondary">
-                CI {lane.ci_status}
-              </span>
-            )}
-            {lane.tool === "codex" && (
-              <span className="rounded border border-border bg-surface-2 px-1.5 py-0.5 text-[10px] text-fg-muted">
-                Codex
-              </span>
-            )}
+            <span className="rounded bg-surface-2 px-1.5 py-0.5 text-fg-secondary">
+              CI {lane.ci_status}
+            </span>
           </div>
         )}
 

client/src/components/lanes/LaneStripCard.tsx

@@ -18,6 +18,7 @@
 import { useState } from "react";
 import { useTranslation } from "react-i18next";
 import type { Lane } from "../../lib/types";
+import { LANE_TOOL_LABEL } from "../../lib/types";
 
 const LIVENESS_DOT: Record<Lane["liveness"], string> = {
   active: "bg-status-success",
@@ -115,18 +116,18 @@ export default function LaneStripCard({
         <span className="shrink-0 text-[10px] font-semibold tracking-widest text-fg-muted">
           #{lane.id}
         </span>
-        {/* Codex lanes carry no pipeline, so no stage chip — the Codex tag
-            takes its place. */}
-        {lane.tool === "codex" ? (
+        {/* Only claude lanes carry a pipeline; the others show their CLI's
+            tag in place of the stage chip. */}
+        {lane.tool !== "claude" ? (
           <span className="shrink-0 rounded border border-border bg-surface-2 px-1.5 py-0.5 text-[10px] text-fg-muted">
-            Codex
+            {LANE_TOOL_LABEL[lane.tool]}
           </span>
         ) : (
           <span className="truncate rounded bg-surface-4 px-1.5 py-0.5 text-fg-secondary">
             {lane.stage}
           </span>
         )}
-        {lane.tool !== "codex" && detectionLeads(lane) && (
+        {lane.tool === "claude" && detectionLeads(lane) && (
           <span
             data-testid={`lane-tile-auto-${lane.id}`}
             title={lane.detected_signal || undefined}

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

@@ -96,13 +96,16 @@ function makeLane(overrides: Partial<Lane> = {}): Lane {
 }
 
 describe("LaneCard lane tool badge", () => {
-  it("badges a codex lane and leaves a claude lane unbadged", () => {
-    const { rerender } = render(
-      <LaneCard {...{ lane: makeLane({ tool: "codex" }), onAction: vi.fn() }} />
-    );
-    expect(screen.getByText("Codex")).toBeInTheDocument();
-    rerender(<LaneCard {...{ lane: makeLane({ tool: "claude" }), onAction: vi.fn() }} />);
-    expect(screen.queryByText("Codex")).not.toBeInTheDocument();
+  // The strip tile already names the CLI; a card holding only that tag was an
+  // empty frame in the lane detail.
+  it("renders nothing for a codex or antigravity lane with nothing else to show", () => {
+    for (const tool of ["codex", "antigravity"] as const) {
+      const { container, unmount } = render(
+        <LaneCard {...{ lane: makeLane({ tool }), onAction: vi.fn() }} />
+      );
+      expect(container.querySelector('[data-testid="lane-card-1"]')).toBeEmptyDOMElement();
+      unmount();
+    }
   });
 });