### What does this PR do?
This PR implements support for the `email` field in `.npmrc` files for
registry scope authentication. Some private registries (particularly
Nexus) require the email field to be specified in the registry
configuration alongside username/password or token authentication.
The email field can now be specified in `.npmrc` files like:
```ini
//registry.example.com/:email=user@example.com
//registry.example.com/:username=myuser
//registry.example.com/:_password=base64encodedpassword
```
### How did you verify your code works?
1. **Built Bun successfully** - Confirmed the code compiles without
errors using `bun bd --debug`
2. **Wrote comprehensive unit tests** - Added two test cases to
`test/cli/install/npmrc.test.ts`:
- Test for standalone email field parsing
- Test for email combined with username/password authentication
3. **Verified tests pass** - Ran `bun bd test
test/cli/install/npmrc.test.ts -t "email"` and confirmed both tests
pass:
```
✓ 2 pass
✓ 0 fail
✓ 6 expect() calls
```
4. **Code changes include**:
- Added `email` field to `NpmRegistry` struct in `src/api/schema.zig`
- Updated `encode()` and `decode()` methods to handle the email field
- Modified `ini.zig` to parse and store the email field from `.npmrc`
- Removed email from the unsupported options warning (certfile and
keyfile remain unsupported)
- Updated all `NpmRegistry` struct initializations to include the email
field
- Updated `loadNpmrcFromJS` test API to return the email field
🤖 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>
