feat: edit in the Changes panel, git graph history, plan quota (v2.3.0)

- Changes panel: a working file opens in a CodeMirror editor with its diff
  inline (DiffEditor.tsx, @codemirror/merge, lazy-loaded); Changes folds the
  unchanged lines, Whole file shows them; side by side at 50/50 and full
  width; a Revert per block; original from HEAD or the branch's merge base
  (`mergeBase` on GET /git/changes?range=branch)
- Every diff: green = line added whole, red = removed whole, blue = edited
  in place (--diff-mod)
- History drawn as a commit graph (#58: `parents` on GET /git/log,
  --date-order; lib/commitGraph.ts)
- Per-workspace never-stage list, drawn orange in the Files tree (--kept);
  closed Terminal rows past three deleted
- Status bar plan quota for Claude (per account) and Codex
  (GET /api/pricing/quota, server/lib/quota.js); compact hover panel that
  stays open, Refresh button with a spinner
- Settings → Appearance holds language, theme and pet; Ctrl+Shift+C copies;
  compact sidebar navigation and short session times

server/__tests__/dashboard-runs.test.js

@@ -61,6 +61,27 @@ describe("dashboard-runs", () => {
     assert.equal(runs.getRun("agenthub-lane-9-1"), null);
   });
 
+  it("keeps only the newest closed Terminal tabs of a lane, live ones untouched", () => {
+    for (let i = 1; i <= 5; i++) {
+      start(`agenthub-lane-11-${i}`, {
+        laneId: 11,
+        tool: "shell",
+        startedAt: Date.parse(`2026-10-0${i}T10:00:00Z`),
+      });
+    }
+    start("agenthub-lane-11", { laneId: 11, tool: "claude", startedAt: Date.parse("2026-09-01") });
+    // Pane 5 still runs; every other one has closed.
+    runs.reconcileOrphans((id) => id === "agenthub-lane-11-5");
+    const shells = runs.listRuns({ laneId: 11, tool: "shell" }).map((r) => r.id);
+    assert.deepEqual(shells, [
+      "agenthub-lane-11-5",
+      "agenthub-lane-11-4",
+      "agenthub-lane-11-3",
+      "agenthub-lane-11-2",
+    ]);
+    assert.ok(runs.getRun("agenthub-lane-11"), "another tool's row stays");
+  });
+
   it("flags as abandoned only the running rows whose pane is gone", () => {
     start("agenthub-lane-5", { laneId: 5 });
     start("agenthub-lane-6", { laneId: 6 });