GUI: Insert-only close, freeze mouse look at the source

Feedback pass:

- Insert now toggles the GUI; the old text tree moved to F1.
- Remove the title-bar X. Insert is the only close path; Esc only cancels
  bind capture.
- Discard accumulated mouse deltas in CInput::CreateMove before the game can
  apply them (CInput::ClearStates), so the camera no longer moves for a frame
  and snaps back. Also skip ExtraMouseSample and zero relative mouse state
  while the GUI is open.
- Strip attack/use/impulse/weapon selection from the command while open;
  keep jump, duck and walk. Skip combat command edits (spread seed) too.
- Widen System page buttons so "Reload config" and "Reset defaults" fit.
- Update CONTEXT/ADR for the Insert-only close behavior.

1 files changed, 3 insertions, 3 deletions

diff --git a/docs/adr/0001-custom-isurface-gui.md b/docs/adr/0001-custom-isurface-gui.md
index 9595ca8..5525844 100644
--- a/docs/adr/0001-custom-isurface-gui.md
+++ b/docs/adr/0001-custom-isurface-gui.md
@@ -54,6 +54,6 @@ path.
 - The GUI remains inside the engine's VGUI paint path, so it inherits the
   existing font registration and in-game overlay behavior.
 - The old text menu is removed once the GUI reaches feature parity. During
-  development the GUI is built alongside the text menu and opened with a
-  temporary F2 key; the replacement is complete only when the old tree is
-  deleted.
+  development the GUI is built alongside the text menu; Insert toggles the
+  GUI and F1 keeps the old tree accessible. The replacement is complete only
+  when the old tree is deleted.