fix: add final unmount render to trigger shouldClearOnUnmount

Ink does an explicit onRender() with isUnmounting=true before unmount
(ink.tsx:755-761), which triggers clearTerminal for fullscreen apps.
vue-tui's teardown() was nulling scheduledCommit before unmount, making
shouldClearOnUnmount dead code. Now calls commit() synchronously before
disabling the scheduler, matching Ink's unmount render behavior.

Restores 2 erase PTY tests that were incorrectly attributed to a
React vs Vue rendering difference.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/runtime-tests/integration/pty/render.test.ts

@@ -51,6 +51,26 @@ it("do not erase screen where <Static> is taller than viewport", async () => {
   }
 });
 
+it("erase screen (content overflows viewport)", async () => {
+  const ps = term("erase", ["3"]);
+  await ps.waitForExit();
+  expect(ps.output).toContain(ansiEscapes.clearTerminal);
+
+  for (const letter of ["A", "B", "C"]) {
+    expect(ps.output).toContain(letter);
+  }
+});
+
+it("erase screen where <Static> exists but interactive part is taller than viewport", async () => {
+  const ps = term("erase-with-static", ["3"]);
+  await ps.waitForExit();
+  expect(ps.output).toContain(ansiEscapes.clearTerminal);
+
+  for (const letter of ["A", "B", "C", "D", "E", "F"]) {
+    expect(ps.output).toContain(letter);
+  }
+});
+
 it("erase screen where state changes", async () => {
   const ps = term("erase-with-state-change", ["4"]);
   await ps.waitForExit();

packages/runtime/src/render.ts

@@ -150,6 +150,7 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
   let mountedGetLastOutput: (() => string) | null = null;
   let mountedRestoreConsole: (() => void) | null = null;
   let mountedScheduler: ReturnType<typeof createCommitScheduler> | null = null;
+  let mountedCommit: (() => void) | null = null;
 
   // The renderer's onCommit closure is wired at createApp time but only does
   // real work after mount swaps in scheduler.schedule. One renderer per app
@@ -185,6 +186,14 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
   function teardown() {
     if (teardownStarted) return;
     teardownStarted = true;
+
+    // Final render before unmount (matching Ink ink.tsx:755-761).
+    // teardownStarted=true makes shouldClearTerminalForFrame see isUnmounting,
+    // so fullscreen apps get clearTerminal on exit.
+    if (mountedInteractive && !mountedDebug && mountedCommit) {
+      mountedCommit();
+    }
+
     scheduledCommit = () => {};
     // Restore console BEFORE Vue cleanup (matching Ink ink.tsx:779)
     if (mountedRestoreConsole) {
@@ -523,6 +532,7 @@ export function createApp(root: Component, rootProps?: RootProps | null): TuiApp
     }
     const scheduler = createCommitScheduler(commit, schedulerOptions);
     mountedScheduler = scheduler;
+    mountedCommit = commit;
     scheduledCommit = scheduler.schedule;
 
     // Internal provides — set before the actual mount so components can inject