#3437 [Other] setup.py WIN_HIP_ASSET still names strata-windows-x64-hip.zip, which no 0.2.x release ships

Beschreibung

`setup.py` at v0.2.1 (commit 90767252) fetches the Windows HIP engine through
`WIN_HIP_ASSET = "strata-windows-x64-hip.zip"` (line 3473) from
`releases/latest/download/`. That asset name no longer exists:

- `releases/download/v0.2.1/strata-windows-x64-hip.zip` returns 404.
- `releases/latest/download/strata-windows-x64-hip.zip` redirects to the v0.2.1
  asset and returns 404.
- The zip shipped through v0.1.45 (the 0.1.45 one has SHA-256 starting
  `75a2ff9c`). The 0.2.0-beta and v0.2.1 releases ship per-GPU names instead:
  `Strata-0.2.1-windows-hip.exe`, `Strata-0.2.1-windows-hip-rdna3.exe`,
  `strata-engine-0.1.46-windows-x86_64-hip-rdna3.tar.gz`,
  `strata-engine-0.1.46-windows-x86_64-hip-rx9070.tar.gz`.

Effect: on a fresh Windows AMD source checkout at v0.2.1, the engine step of
setup fails with "no ready-made AMD engine for this Strata version" and points
at self-building (`tools\hip\build_windows.bat` plus `START-HERE.bat
--prebuilt`). Machines that installed a 0.1.45 engine earlier are unaffected
until they need a fetch again, because `update_installed_engine` only fetches
when the installed engine is older than 0.1.45. `docs/AMD_HIP.md` (around line
136) still tells users to take the zip "from the release".

Reproduction status: the 404s are live checks. The setup hard-fail text is
code reading, not an executed run (my installed engine passes the minimum, so
the fetch path did not trigger on my machine).

Environment: Windows 10 build 19044, source checkout at tag v0.2.1, AMD Radeon
RX 7900 XTX 24 GB, engine 0.1.45 prebuilt installed.

Suggested fix: teach `WIN_HIP_ASSET` the per-GPU package names (the GPU is
known at setup time), or ship a flat zip again alongside the per-GPU packages.