fix(cli): ignore terminal focus reports (salvage of #16780)

Ghostty/macOS window or tab navigation (Cmd+Shift+[ / ], Alt+Tab,
etc.) can deliver terminal focus reports (CSI I / CSI O) to the
running TUI. prompt_toolkit does not map those sequences by default,
so its parser falls back to literal key presses (ESC, [, I/O) and
inserts `[I` / `[O` into the prompt buffer after the ESC byte is
handled.

Fix: register the two sequences as Keys.Ignore in ANSI_SEQUENCES at
parser level, plus a no-op kb.add(Keys.Ignore) handler so the
default self-insert path never inserts focus-report bytes.

Salvage notes: original PR put the helper in cli.py. Salvaged into
hermes_cli/pt_input_extras.py alongside install_shift_enter_alias /
install_ctrl_enter_alias to match the established pattern for
ANSI_SEQUENCES augmentation. setdefault → in-check so any prior user
registration wins.

Closes #16780

tests/cli/test_cli_terminal_shortcuts.py

@@ -0,0 +1,49 @@
+"""Regression tests for terminal navigation/focus escape sequences.
+
+Ghostty/macOS window and tab navigation can deliver terminal focus reports
+(CSI I / CSI O) to the running TUI. These must be consumed by the input parser,
+not inserted into the prompt buffer and cleaned up later.
+"""
+
+from prompt_toolkit.input.vt100_parser import Vt100Parser
+from prompt_toolkit.keys import Keys
+
+from hermes_cli.pt_input_extras import install_ignored_terminal_sequences
+
+
+def _parse_keys(data: str):
+    events = []
+    parser = Vt100Parser(events.append)
+    parser.feed_and_flush(data)
+    return [(event.key, event.data) for event in events]
+
+
+def test_focus_events_are_parser_level_ignored_before_prompt_buffer():
+    install_ignored_terminal_sequences()
+
+    assert _parse_keys("\x1b[O\x1b[Ihello") == [
+        (Keys.Ignore, "\x1b[O"),
+        (Keys.Ignore, "\x1b[I"),
+        ("h", "h"),
+        ("e", "e"),
+        ("l", "l"),
+        ("l", "l"),
+        ("o", "o"),
+    ]
+
+
+def test_regular_escape_shortcuts_still_parse_normally():
+    install_ignored_terminal_sequences()
+
+    assert _parse_keys("\x1bg") == [(Keys.Escape, "\x1b"), ("g", "g")]
+
+
+def test_install_is_idempotent_and_setdefault_safe():
+    """Second call should return 0 (no new mappings); existing user
+    registrations must not be overwritten."""
+    first = install_ignored_terminal_sequences()
+    second = install_ignored_terminal_sequences()
+    # At most first should be 2 (both CSI I + CSI O), second always 0
+    # since the entries are now present.
+    assert second == 0
+    assert first in (0, 1, 2)  # 0 if a prior test in same process already installed