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, 2 insertions, 1 deletions

diff --git a/src/hl2h.cpp b/src/hl2h.cpp
index a0e6b53..1460577 100644
--- a/src/hl2h.cpp
+++ b/src/hl2h.cpp
@@ -561,7 +561,8 @@ static void do_move(int seq, float frametime) {
       cmd->buttons = 0;
     } else {
       // Movement is allowed while the GUI is open, but not look/attack/use.
-      cmd->buttons &= (IN_JUMP | IN_DUCK);
+      // Keep locomotion buttons (jump, duck, walk) only.
+      cmd->buttons &= (IN_JUMP | IN_DUCK | IN_SPEED);
     }
     cmd->impulse = 0;
     cmd->weaponselect = 0;