Track Android host-override integrations across emulators

[misantronic]

Track the upstream status of Android host-override support across emulator integrations used by RAOfflineProxy.

Why:

• RAOfflineProxy works best when emulators expose a clean Android-side host-override mechanism instead of requiring direct config patching
• Several emulator integrations are now in flight or already merged upstream
• Tracking them in one place makes follow-up easier as upstream PRs evolve and ship

Current upstream status:

• ARMSX2: merged and released in a nightly build
• PPSSPP: merged and planned for the next release
• Flycast: merged
• melonDS: declined upstream. Support is being integrated into the melonDualDS fork instead, so no upstream change is needed.
• melonDualDS: support in progress in the fork (see discussion below)
• Dolphin: PR open, pending review
• RetroArch: PR open, pending review

Tracked upstream PRs:

Merged:

• ARMSX2: Android: Add RetroAchievements host override receiver ARMSX2/ARMSX2#164
• PPSSPP: Android: add achievements host override receiver hrydgard/ppsspp#21760
• Flycast: Android: Add RetroAchievements host override receiver flyinghead/flycast#2371
  • android: allow cleartext HTTP to 127.0.0.1 for local proxy image loading flyinghead/flycast#2379 — allow cleartext HTTP to 127.0.0.1 so badge/icon images load from the proxy
  • achievements: retry login when host override is set and login previously failed flyinghead/flycast#2380 — retry login automatically when host override is set after a failed login attempt

Closed:

• melonDS: Android: add RetroAchievements host override receiver rafaelvcaetano/melonDS-android#1633 — declined upstream; covered by the melonDualDS fork instead

Open:

• Dolphin: Android: Add RetroAchievements host override receiver dolphin-emu/dolphin#14671
• RetroArch: Android: add RetroAchievements host override receiver libretro/RetroArch#19093

Other:

• melonDualDS: Add suport por melonDualDS #38 — RAOfflineProxy support being integrated in the fork