v0.3.1-alpha — ROM file picker on first launch

v0.3.0-alpha + file picker. Same recompiled core; first-launch
UX changed only.

What's new

• Runner now pops a native Win32 file picker if no ROM is configured
  (no rom.cfg next to the exe, no baserom.z64 discoverable, no
  CLI arg).
• Successful picks are saved to rom.cfg so subsequent launches
  go straight into the game.
• ROM validation (MD5 match against Pokémon Stadium US v1.0) still
  enforced. On mismatch you get a clear MessageBox with the expected
  hash and the picker reopens.
• argv[1] still honored for scripted runs.

This replaces the v0.3.0-alpha requirement to manually rename and
drop baserom.z64 next to the exe before the first launch.

Setup

1. Download PokemonStadiumRecomp-v0.3.1-alpha-win64.zip and extract.
2. Double-click PokemonStadiumRecomp.exe.
3. Pick your own legal Pokémon Stadium (US v1.0) ROM when prompted.

Everything else (game scope, audio, bugs, requirements)

Same as v0.3.0-alpha — see that release's notes or
ISSUES.md.

Engine pins

• N64Recomp: ss-anne/N64Recomp@fad8a9c
• RT64: ss-anne/rt64@1bc1b79
• N64ModernRuntime: ss-anne/N64ModernRuntime@90e12f0