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

Tracked upstream PRs:

Merged:

• ARMSX2: Android: Add RetroAchievements host override receiver ARMSX2/ARMSX2#164
• ARMSX2 Refresh: Android: add RetroAchievements host override receiver ARMSX2/ARMSX2#209 — merged into refresh-experimental and released in tag 2.3.4
• 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
• mupen64plus-ae: Add RetroAchievements host-override broadcast receiver JoeysRetroHandhelds/mupen64plus-ae-retroachievements#1 — merged into the RetroAchievements fork; will carry over to the official mupen64plus-ae when the fork's RA work is upstreamed

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
• NetherSX2: Add RetroAchievements host-override broadcast receiver Trixarian/NetherSX2-patch#343

Other:

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

Linux / ROCKNIX

• ROCKNIX/distribution: Add custom RetroAchievements host support to standalone Dolphin ROCKNIX/distribution#3038 — open. Adds HostUrl support to Dolphin's cheevos_dolphin.sh, which currently wipes any custom host on every launch. Verified working end-to-end on hardware via a local test rig.
• RAOfflineProxy Dolphin support: Add Dolphin support for ROCKNIX #50 — depends on the PR above; no effect until it ships.
• RAOfflineProxy PPSSPP support (ROCKNIX): merged (main), works today.