#359 fix: publish ARM64 local-mode wheels

Summary

• add Linux ARM64 and Windows ARM64 wheel targets to the publish matrix
• map those targets to the SEA asset names already produced by the release pipeline
• add resolver tests for x64 and ARM64 filenames on Linux and Windows

The packaging jobs only download and bundle architecture-specific assets, so the existing hosted x64 runners can produce these pure-Python platform-tagged wheels without executing the bundled binary.

Testing

• uv run --frozen pytest tests/test_sea_binary.py -q (8 passed)
• uv run --frozen ruff check .
• uv run --frozen pyright -p .
• uv run --frozen mypy --platform linux .
• full Python 3.9 and 3.14 suites run on Windows; only the pre-existing Windows failures addressed by #355 remained

Fixes #352

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Summary by cubic

Publishes ARM64 wheels for Linux and Windows in local mode. Previously we only shipped x64 wheels; now we also build manylinux2014_aarch64 and win_arm64 to enable ARM64 installs without source builds.

• Map new matrix entries to existing SEA assets: stagehand-server-v3-linux-arm64 and stagehand-server-v3-win32-arm64.exe.
• Add tests that assert default binary filenames for Linux and Windows on x64 and ARM64.
• Use hosted x64 runners only; packaging downloads architecture-specific assets and does not execute them. No runtime behavior change.