feat(ui): add session history navigation, permission keys, and review shortcuts

mod+alt+arrows step through this window's session-open history (or between
neighbouring tabs when session tabs are on), mod+k r renames the current
session inline, and mod+k a toggles permission auto-accept. Pending
permission cards respond to alt+enter / alt+shift+enter / alt+backspace with
the keys printed on the buttons. The commit message box commits on
mod+enter, alt+arrows step the diff review between changed files, and the
command palette gains search-only commands for rare actions so the initial
list stays short.

packages/ui/src/lib/sessionNavigationHistory.test.ts

@@ -0,0 +1,50 @@
+import { describe, expect, test } from 'bun:test';
+import type { Session } from '@opencode-ai/sdk/v2';
+import { navigateSessionHistory } from './sessionNavigationHistory';
+import { useSessionUIStore } from '@/sync/session-ui-store';
+import { useGlobalSessionsStore } from '@/stores/useGlobalSessionsStore';
+
+// SAFETY: the history module only reads a session's id and directory metadata.
+const session = (id: string): Session => ({
+  id,
+  title: id,
+  directory: '/repo',
+  projectID: 'p1',
+  version: '1',
+  time: { created: 1, updated: 1 },
+} as Session);
+
+describe('sessionNavigationHistory', () => {
+  test('steps back and forward through the visit order', () => {
+    useGlobalSessionsStore.setState({ activeSessions: [session('s1'), session('s2'), session('s3')] });
+
+    useSessionUIStore.setState({ currentSessionId: 's1' });
+    useSessionUIStore.setState({ currentSessionId: 's2' });
+    useSessionUIStore.setState({ currentSessionId: 's3' });
+
+    expect(navigateSessionHistory(-1)).toBe(true);
+    expect(useSessionUIStore.getState().currentSessionId).toBe('s2');
+    expect(navigateSessionHistory(-1)).toBe(true);
+    expect(useSessionUIStore.getState().currentSessionId).toBe('s1');
+    expect(navigateSessionHistory(-1)).toBe(false);
+
+    expect(navigateSessionHistory(1)).toBe(true);
+    expect(useSessionUIStore.getState().currentSessionId).toBe('s2');
+  });
+
+  test('a fresh visit truncates the forward branch', () => {
+    // Continues from the previous test's state: at s2 with s3 forward.
+    useSessionUIStore.setState({ currentSessionId: 's1' });
+    expect(navigateSessionHistory(1)).toBe(false);
+    expect(navigateSessionHistory(-1)).toBe(true);
+    expect(useSessionUIStore.getState().currentSessionId).toBe('s2');
+  });
+
+  test('skips and drops entries whose session no longer exists', () => {
+    useSessionUIStore.setState({ currentSessionId: 's3' });
+    useGlobalSessionsStore.setState({ activeSessions: [session('s1'), session('s3')] });
+    // History behind s3 contains s2 (dead) then s1 (alive).
+    expect(navigateSessionHistory(-1)).toBe(true);
+    expect(useSessionUIStore.getState().currentSessionId).toBe('s1');
+  });
+});