Address review findings from PR #1256 across Node, Python, Go, Java,
and Elixir extractors:
- Replace hardcoded IGNORE sets with shared IgnoreService
(shouldIgnorePath + loadIgnoreRules) to honor .gitnexusignore
- Qualify contract names with provider identifier to prevent
contractId collisions across providers
- Warn and skip duplicate project/module/app names
- Update all test assertions for qualified contract format