Reset the terminal before opening the LXC shell

Write ESC c, the sequence `reset` sends, inside suspend() right before
ssh. The container shell then starts on a clean screen with no
leftover TUI terminal modes. It runs locally, so the container does
not need `reset` installed and `pct enter` is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/plans/guest-tui-mvp.md

@@ -210,6 +210,10 @@ root's `authorized_keys` (verified: `ssh -o BatchMode=yes root@mainframe pct sta
 - Exit 255 (ssh itself failed) -> error notify naming the guest and the code. Other
   exit codes are the container shell's last status (`exit` after a failed command
   gives 1) and are not errors.
+- Inside `suspend()`, right before ssh, the terminal gets a full reset (`ESC c`, what
+  `reset` sends) so the container shell starts on a clean screen without leftover TUI
+  terminal modes (user request). Done locally, not in the container: no dependency on
+  `reset` existing there, and `pct enter` stays unchanged.
 - `OSError` from `subprocess.run` is caught *inside* the `suspend()` block: Textual
   8.2.8's `suspend()` has no try/finally, so an exception escaping it leaves the app
   suspended.

src/cv4pve_tui/app.py

@@ -1,6 +1,7 @@
 """Textual app for managing Proxmox guests through cv4pve-cli."""
 
 import subprocess
+import sys
 
 from textual import work
 from textual.app import App, ComposeResult, SuspendNotSupported
@@ -358,6 +359,7 @@ class GuestApp(App):
         try:
             with self.suspend():
                 try:  # inside: Textual's suspend() skips the resume if its body raises
+                    _reset_terminal()
                     code = subprocess.run(cmd, check=False).returncode
                 except OSError as exc:
                     error = _message(exc)
@@ -426,6 +428,12 @@ class GuestApp(App):
         self._start_job(guest, "edit", job)
 
 
+def _reset_terminal() -> None:
+    """Full terminal reset (ESC c, what `reset` sends): clean screen, no leftover TUI modes."""
+    sys.stdout.write("\033c")
+    sys.stdout.flush()
+
+
 def _scaled(value, unit: int):
     return "-" if value is None else round(value / unit)
 

tests/test_app.py

@@ -907,3 +907,17 @@ async def test_table_reloads_after_shell(fake, monkeypatch):
         await press_t(app, pilot)
         await settle(app, pilot)
         assert fake.list_calls > before
+
+
+async def test_terminal_is_reset_inside_suspend_before_ssh(fake, monkeypatch):
+    # user request: a clean screen (and no leftover TUI terminal modes) in the container shell
+    fake.guests = [RUNNING_CT]
+    app = make_app()
+    events = patch_shell(monkeypatch, app)
+    resets = []
+    monkeypatch.setattr(
+        "cv4pve_tui.app._reset_terminal", lambda: resets.append(list(events))
+    )
+    async with app.run_test() as pilot:
+        await press_t(app, pilot)
+        assert resets == [[("enter", None)]]  # inside suspend, before ssh ran