Slack Onboarding Improvements & Data Quality Fixes

New Features

• Adds a "Force onboarding" button to the Slack bot reply when a project evaluation is skipped or uncertain, enabling immediate manual override without re-submitting the request.
• Extends per-repo Slack review alerts to projects submitted via the Slack bot, ensuring all onboarding requests trigger the appropriate notifications.

Improvements

• Tightens documentation URL discovery by filtering out third-party product docs from README links and applying stricter search result relevance.
• Improves documentation readiness sweep throughput by keeping all concurrency slots active throughout the entire run.

Bug Fixes

• Fixes project onboarding incorrectly reusing an existing unrelated project segment when a matching name is found.
• Corrects repo-to-package linking in impact pipelines for repositories whose URLs differ only by letter casing.
• Resolves organization enrichment stalls caused by the AI model selecting an invalid primary domain.
• Fixes a data sync edge case where unconfirmed candidates were incorrectly flagged as missing records.
• Resolves frontend circular import issues that could affect application loading.