## Summary
Fixes environment variable expansion in quoted `.npmrc` values and adds
support for the `?` optional modifier.
### Changes
**Simplified quoted value handling:**
- Removed unnecessary `isProperlyQuoted` check that added complexity
without benefit
- When JSON.parse succeeds for quoted strings, expand env vars in the
result
- When JSON.parse fails for single-quoted strings like `'${VAR}'`, still
expand env vars
**Added `?` modifier support (matching npm behavior):**
- `${VAR}` - if VAR is undefined, leaves as `${VAR}` (no expansion)
- `${VAR?}` - if VAR is undefined, expands to empty string
This applies consistently to both quoted and unquoted values.
### Examples
```ini
# Env var found - all expand to the value
token = ${NPM_TOKEN}
token = "${NPM_TOKEN}"
token = '${NPM_TOKEN}'
# Env var NOT found - left as-is
token = ${NPM_TOKEN} # → ${NPM_TOKEN}
token = "${NPM_TOKEN}" # → ${NPM_TOKEN}
token = '${NPM_TOKEN}' # → ${NPM_TOKEN}
# Optional modifier (?) - expands to empty if not found
token = ${NPM_TOKEN?} # → (empty)
token = "${NPM_TOKEN?}" # → (empty)
auth = "Bearer ${TOKEN?}" # → Bearer
```
### Test Plan
- Added 8 new tests for the `?` modifier covering quoted and unquoted
values
- Verified all expected values match `npm config get` behavior
- All 30 ini tests pass
🤖 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>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
