#7676 feat(slack): improve source connections and app Home

Summary

• Add a persistent Slack Home tab with a Connect sources button linking to the existing Sim Integrations page. Publish on first visits and when the saved layout, credential, or app origin changes; current views skip Home lookup, queue, and publish work.
• Keep Home static: no source-status queries, Slack email lookup, or invitation links. Recheck installation bindings before publishing and let Sim authorize access to the destination. Enable Home in the setup manifest without adding scopes.
• Expose Slack account setup removal from Sources and Accounts, preserving other providers and refreshing organization-scoped setup caches.
• Render verified citations inline beside the answer text and remove the trailing source footer.

Type of Change

• Feature
• Bug fix

Testing

• 340 focused tests across 27 suites passed, including Home routing, saved-view reuse and invalidation, installation isolation, cancellation, failed delivery, existing Slack ingress, and Assistant behavior.
• App/auth typechecks, lint, all 46 repository audits, block registry, and docs manifest checks passed.
• Earlier account-removal validation passed 176 tests across 11 suites.
• The Home tab and new inline citation presentation have not been smoke-tested in live Slack. Existing apps need Home enabled in their Slack configuration.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)