GeezerVison

Summary

When pre-built Python binaries are not available for the current architecture, fall back to system Python instead of failing with an error.

This enables setup-python to work on architectures like riscv64 that don't yet have pre-built binaries in actions/python-versions. RISC-V self-hosted runners are becoming available through programs like RISE RISC-V runners, used by numpy, llama.cpp, and pytorch.

Changes

• src/find-python.ts: Before throwing "version not found" error, check if system python3 exists and satisfies the requested version spec. If so, use it and emit a warning.

Behavior

• No change for architectures with pre-built binaries (x86_64, arm64, etc.)
• On unsupported architectures (riscv64, etc.): uses system Python if version matches, warns user
• Still fails if system Python doesn't satisfy the version spec

Test plan

• Builds successfully (npm run build)
• Verify on riscv64 self-hosted runner with system Python 3.12

Fixes #1288