Add support for --linker flag to set node_linker strategy:
- `bun install --linker isolated` forces isolated node linker
- `bun install --linker hoisted` forces hoisted node linker
Changes:
- Add --linker CLI flag parsing with validation
- Store CLI node_linker override in PackageManagerOptions
- Apply CLI override in two locations where lockfile is initialized
- Add comprehensive tests for flag validation and functionality
- Update help text with examples
The CLI flag takes precedence over package.json and lockfile settings,
ensuring consistent behavior across different project configurations.
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Co-Authored-By: Claude <noreply@anthropic.com>