Mega Man X4 Recompiled — v0.1.1-coop-playtest.4

Linux AppImage co-op regression release, with the gameplay fixes validated
on Windows. Unified remains the default, and Split cameras remain experimental.

• Netplay hosting starts the game with the selected BIOS, fixing the white
  screen after Play. Shared launcher and network dependencies are updated.
• Both players use paired native arrivals for stage entry, forward sections
  and team retry. Cyber Peacock course portals return living players to safe
  native landings; boss approaches preserve the surviving player's controls.
• Dash exhaust, trails and delayed attack effects use their allocating
  character and position. Ride Chaser riders, bikes and exhaust stay together;
  Zero's fire/ice fragments and X's special effects retain their own graphics.
• Shared dialogue setup preserves the native palette. Pause fades retain the
  partner body, effects and HUD, with character textures preserved across scenes.
• P1 owns the campaign and permanent upgrades. Continue, native cards and
  cleared portraits retain that progress through Quit and Escape Device returns.
• A surviving P2 can continue native stage transitions after P1 dies.
• Zero can use the partner's Lightning Web as a native wall-jump anchor.
• Both Split views keep the train scenery moving during Slash Beast's fight.

The stable October 10 checklist
tracks all 28 reports and their individual evidence; all entries are checked.
All 18 title checks pass. Native two-peer Split tests cover either player
leading into Slash Beast's fight, with matching state checks through tick8672.
The Linux production build also passes all 18 checks, AppImage layout/seeding,
and hidden launcher TCP smoke tests of the real Netplay button and two-player
controls. Private development controls are disabled. These tests cover the
reported cases rather than complete campaigns or production FPS.

The Windows/Linux launcher retains its two-player lobby and two independent
local controller assignments. Stacked HUD remains the default, with Side by
side available. Playtest Diagnostics remains enabled by default and records
accepted inputs plus starting cards/mod choices under saves/diagnostics.
Use matching builds and OpenGL on both peers, with a fresh boot after mod changes.