feat: soft j/k field navigation in New Session dialog

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_tui.py

@@ -1913,3 +1913,54 @@ def test_dialog_focus_highlight_uses_accent():
     ):
         assert selector in css, f"missing focus rule: {selector}"
     assert "border: tall $accent;" in css
+
+
+def test_new_session_has_jk_focus_bindings():
+    """j -> focus_next, k -> focus_previous, declared on the screen."""
+    from hqt.tui.screens.new_session import NewSessionScreen
+
+    actions = {b.key: b.action for b in NewSessionScreen.BINDINGS}
+    assert actions.get("j") == "focus_next"
+    assert actions.get("k") == "focus_previous"
+
+
+@pytest.mark.asyncio
+async def test_jk_moves_focus_between_controls():
+    """On a non-text control, j moves focus to another control."""
+    app = HqtApp()
+    async with app.run_test(size=(120, 40)) as pilot:
+        from hqt.tui.screens.new_session import NewSessionScreen
+        from textual.widgets import Switch
+
+        app.push_screen(
+            NewSessionScreen(["claude"], is_git_repo=True, sandbox_available=True)
+        )
+        await pilot.pause()
+        switch = app.screen.query_one("#sandbox-switch", Switch)
+        switch.focus()
+        await pilot.pause()
+        assert app.focused is switch
+
+        await pilot.press("j")
+        await pilot.pause()
+        assert app.focused is not switch
+
+
+@pytest.mark.asyncio
+async def test_jk_typed_into_input_is_literal():
+    """Inside a text input, j/k type literally and do not move focus."""
+    app = HqtApp()
+    async with app.run_test(size=(120, 40)) as pilot:
+        from hqt.tui.screens.new_session import NewSessionScreen
+        from textual.widgets import Input
+
+        app.push_screen(NewSessionScreen(["claude"], is_git_repo=True))
+        await pilot.pause()
+        nickname = app.screen.query_one("#nickname-input", Input)
+        nickname.focus()
+        await pilot.pause()
+
+        await pilot.press("j", "k")
+        await pilot.pause()
+        assert nickname.value == "jk"
+        assert app.focused is nickname