Barrel Cleanup: Event & Handler Group

[nnoce14]

Goal: Remove index.ts barrel files and re-export patterns from @ocom/event-handler and @cellix/event-bus-seedwork-node. Refactor imports and add error-level Biome overrides for each package. Merge conflicts handled during PR merges.

Scope: packages/ocom/event-handler, packages/cellix/event-bus-seedwork-node

Tasks:

• Audit index.ts / pure barrels in both packages
• Remove barrel files
• Refactor any import chains
• Add Biome error overrides
• Run lint/build/tests

Success Criteria:

• Packages free of barrel files/star re-exports
• Biome config error overrides present
• All tests/builds pass

Checklist:

• Audit barrels (@ocom/event-handler)
• Audit barrels (@cellix/event-bus-seedwork-node)
• Remove barrels/refactor imports
• Add Biome overrides
• Run verify