fix(CLI Tool): #3591717 Flat named component validation in @drupal-canvas/eslint-config misses sibling entrypoints

• Detect every active flat named component entrypoint in @drupal-canvas/eslint-config.
• Keep named metadata precedence aligned with component discovery.
• Add regression coverage for sibling flat entrypoints and explicit entrypoint imports.

Closes #3591717. Authored with an AI coding agent.