Update vite.config.ts to follow setup-vp bundling style

[torn4dom4n]

This PR updates the Vite+ configuration to align with the bundling style used in @voidzero-dev/setup-vp.

Key changes:

1. Refactored the pack configuration in vite.config.ts from a single object to an array of objects. This forces tsdown to generate separate, self-contained ESM bundles for detect-env.mjs, run-scripts.mjs, and setup.mjs, eliminating the shared core-*.mjs chunk.
2. Enabled alwaysBundle: [/.*/] for all entries to ensure all dependencies (like @actions/core) are bundled into the output files.
3. Updated the minify configuration to preserve function and class names. This is critical for compatibility with libraries that perform brand checks based on constructor names (e.g., @actions/core and @actions/cache).
4. Verified that the dist/ directory no longer contains core-*.mjs and that the generated scripts remain functional via vp test.

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PR created automatically by Jules for task 243303797235888224 started by @torn4dom4n

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