feat: add comprehensive end-to-end test suite

e2e/test_grid_navigation.ts

@@ -0,0 +1,49 @@
+import { setupTest, startEngine, startClientInTmux, tmuxSendKeys, wait, tmuxCapturePane, waitForPaneText, teardownTest } from './test_utils';
+
+export async function testGridNavigation(): Promise<void> {
+  console.log("\nTest: GRID NAVIGATION");
+  setupTest();
+  const engine = await startEngine();
+  await startClientInTmux();
+
+  // Default location should be Row 0, Col 0
+  let pane = await waitForPaneText("Selected: Grid 0, Row 0, Col 0", 5000);
+  if (pane.includes("Selected: Grid 0, Row 0, Col 0")) {
+    console.log("  PASS: Default selection at origin");
+  } else {
+    console.log("  FAIL: Expected 'Selected: Grid 0, Row 0, Col 0'");
+    console.log("  Actual pane content:\n" + pane);
+    engine.kill(); teardownTest();
+    throw new Error("Grid navigation test failed");
+  }
+
+  // Move right then down
+  tmuxSendKeys("looper", "0", "l");
+  tmuxSendKeys("looper", "0", "j");
+  await wait(200);
+  pane = tmuxCapturePane("looper", "0");
+  if (pane.includes("Selected: Grid 0, Row 1, Col 1")) {
+    console.log("  PASS: Moved to Row 1, Col 1");
+  } else {
+    console.log("  FAIL: Expected 'Row 1, Col 1'");
+    engine.kill(); teardownTest();
+    throw new Error("Grid navigation test failed");
+  }
+
+  // Cycle back to origin
+  tmuxSendKeys("looper", "0", "h");
+  await wait(400);
+  tmuxSendKeys("looper", "0", "k");
+  await wait(400);
+  pane = tmuxCapturePane("looper", "0");
+  if (pane.includes("Selected: Grid 0, Row 0, Col 0")) {
+    console.log("  PASS: Returned to origin");
+  } else {
+    console.log("  FAIL: Not at origin after h/k");
+    engine.kill(); teardownTest();
+    throw new Error("Grid navigation test failed");
+  }
+
+  engine.kill();
+  teardownTest();
+}