fix(cli): retire the 0.0 monotonic sentinel in the remaining input-mode throttles

Review follow-up on #91651: _recover_terminal_input_modes and the termios
drift check used the same `now - 0.0 < interval` idiom as the repaint
throttles. Their windows (0.5s / 1.0s) are unreachable in practice, but
converting them to the None sentinel retires the bug class instead of the
instance, so nobody "simplifies" a None back to 0.0 later. Also adds the
missing regression test for _invalidate, the throttle the PR title is about.

cli.py

@@ -2635,7 +2635,7 @@ class HermesCLI(CLIProcessNotificationsMixin, CLIAgentSetupMixin, CLICommandsMix
         self._stream_table_buf: list[str] = []
         self._in_stream_table = False
         self._pending_edit_snapshots = {}
-        self._last_input_mode_recovery = self._last_termios_drift_check = 0.0
+        self._last_input_mode_recovery = self._last_termios_drift_check = None  # None = never; monotonic epoch is arbitrary
         self._input_mode_recovery_notice_shown = self._termios_drift_notice_shown = False
 
     def _init_model_routing(self, model, toolsets, provider, reasoning, api_key, base_url, max_turns, run_budget, checkpoints, pass_session_id, ignore_rules):

hermes_cli/cli_terminal_mixin.py

@@ -367,8 +367,10 @@ class CLITerminalMixin:
             CLI_CONFIG, _DIM, _RST, _TERMINAL_INPUT_MODE_RESET_SEQ,
             _cli_multiline_shortcuts_enabled, _cprint, _enable_extended_enter_keys, logger)
         now = time.monotonic()
-        # Rate-limit to avoid thrashing if a terminal floods reports.
-        if now - self._last_input_mode_recovery < 0.5:
+        # Rate-limit to avoid thrashing if a terminal floods reports. None = never
+        # (monotonic epoch is arbitrary, see _invalidate).
+        last = self._last_input_mode_recovery
+        if last is not None and now - last < 0.5:
             return
         self._last_input_mode_recovery = now
         app = getattr(self, "_app", None)
@@ -408,7 +410,8 @@ class CLITerminalMixin:
         if getattr(app, "_running_in_terminal", False):
             return
         now = time.monotonic()
-        if now - self._last_termios_drift_check < 1.0:
+        last = self._last_termios_drift_check  # None = never (monotonic epoch is arbitrary)
+        if last is not None and now - last < 1.0:
             return
         self._last_termios_drift_check = now
         try:

tests/hermes_cli/test_cli_force_redraw.py

@@ -444,3 +444,16 @@ class TestFocusRegainRedraw:
         bare_cli._schedule_focus_regain_redraw(min_interval=60.0)
 
         assert calls == ["redraw"]
+
+    def test_first_invalidate_fires_even_with_small_monotonic_clock(
+        self, bare_cli, monkeypatch
+    ):
+        """Same class as above for the streaming/spinner repaint throttle."""
+        app = MagicMock()
+        bare_cli._app = app
+        bare_cli._last_invalidate = None
+        monkeypatch.setattr(cli_mod.time, "monotonic", lambda: 0.1)
+
+        bare_cli._invalidate(min_interval=0.25)
+
+        app.invalidate.assert_called_once()