Fix stale removal comments (persistent, not destroy) + add deterministic install test

- The remove_* comments still described the superseded "disable -> drain -> destroy"
  flow; the code keeps hooks alive (persistent) and re-enables on re-install. Updated
  the comments to match, and corrected the XInput note (its detours return synthesized
  state and never call the trampoline, so destroying its vector is safe -- unlike the
  trampoline-calling present/MKB/focus-cursor hooks).
- hook_install_test: a fast, single-threaded contract test for hook_install.hpp --
  install_inline creates the hook once and reuses the SAME trampoline across 50
  install/remove cycles (never freed -> no stale-detour UAF), toggling enable/disable
  cleanly. Fills the guard the removed (flaky, concurrency-bound) reproducer left, with
  no threads so it can't flake on SafetyHook's enable/disable atomicity.

x64 23/23, x86 3/3.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

hook/src/opengl_hook.cpp

@@ -323,11 +323,11 @@ bool install_opengl_hooks(IpcClient& ipc)
 
 void remove_opengl_hooks()
 {
-	// DISABLE (not destroy) first: restores the SwapBuffers bytes under thread suspension (no new
-	// detour) but keeps the trampolines alive, so an in-flight detour about to call .stdcall() (the
-	// trampoline) doesn't have it freed under it. Destroying (= {}) before the drain frees the
-	// trampoline immediately -- a UAF the uncapped mock-game storm (thousands of swaps/s) can hit.
-	// Disable -> drain -> only then destroy.
+	// DISABLE (persistent model -- never destroy during the session): restores the SwapBuffers bytes
+	// under thread suspension (no new detour) but keeps the trampolines alive, so an in-flight detour
+	// about to call .stdcall() (the trampoline) never has it freed under it. Destroying (= {}) would
+	// free it -- a UAF the thousands/s storm can hit. Disable -> drain -> leave alive (re-install
+	// re-enables; see hook_install.hpp).
 	disable_for_removal(g_hk_swapbuffers);
 	disable_for_removal(g_hk_wglswap);
 	hook_set_installed(g_id_swapbuffers, false);