Ability to bind Additional Mouse Buttons + Alt Key

[AL2009man]

During the work on both #296 and #295: I've discover the way to bypass Red Faction 1's stock bindings by utilizing CTRL_REBIND_SENTINEL = 0x58 for it.

This PR will let you bind additional inputs for Mouse Input, while enabling Alt key (both Left and Right Alt keys)

edit: will be adding it to changelog a bit later

[Copilot]

Pull request overview

Adds support for binding additional mouse buttons (via WM_XBUTTON*) and Left/Right Alt in Red Faction’s controls UI by injecting a “rebind sentinel” scan code and post-processing the binding result into custom scan codes stored in the control config.

Changes:

• Suppress the Windows Alt “menu activation” system command and forward XBUTTON down/up events into the game input pipeline.
• Track pending “extra” inputs (mouse XBUTTONs and Alt) during the rebind flow and swap the sentinel binding to the intended scan code once the UI exits “waiting for key”.
• Extend key name rendering to display friendly names for the custom “Mouse 4+” scan codes; document the feature in the changelog.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
game_patch/os/os.cpp	Swallows SC_KEYMENU and routes WM_XBUTTONDOWN/UP to the mouse input handler.
game_patch/misc/ui.cpp	Detects end of rebind capture and replaces the sentinel binding with the pending extra input scan code.
game_patch/input/mouse.h	Exposes a Win32 XBUTTON message handler entry point.
game_patch/input/mouse.cpp	Implements pending XBUTTON rebind capture + emits custom scan codes for extra mouse buttons.
game_patch/input/key.cpp	Captures Alt during rebind (via sentinel) and adds friendly names for extra mouse scan codes.
game_patch/input/input.h	Introduces the sentinel and custom scan code constants + pending-rebind accessors.
docs/CHANGELOG.md	Adds changelog entries for extra mouse buttons and Alt binding support.

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