## Summary
This PR improves the correctness of bin linking by atomically
normalizing `\r\n` to `\n` in shebang lines when linking bins.
### Changes
- **Refactored shebang normalization in `src/install/bin.zig`**:
- Extracted logic into separate `tryNormalizeShebang` function
- Changed from in-place file modification to atomic file replacement
- Reads entire file, creates temporary file with corrected shebang, then
atomically renames
- Properly cleans up temporary files on errors
- **Added test coverage**:
- New test file `test/cli/install/shebang-normalize.test.ts` verifies
CRLF normalization works correctly
- Modified existing test in `bun-link.test.ts` to use Python script with
CRLF shebang
### Why
The previous implementation modified files in-place by seeking to the
`\r` position and overwriting with `\n`. This could potentially corrupt
files if interrupted mid-write. The new atomic approach ensures file
integrity by writing to a temporary file first, then renaming it to
replace the original.
## Test plan
- ✅ `bun bd test test/cli/install/shebang-normalize.test.ts` - passes
- ✅ Verified bins with CRLF shebangs are normalized to LF during linking
- ✅ Code compiles successfully
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>
