chore(ui): remove dead forge exports and unused useForgeProvider hook

- Remove useForgeProvider React hook (dead; only imperative
  getForgeProviderForDirectory was used, by tests)
- Remove toLookupOptions export from useForgeLookup (only used
  within file)
- Remove ForgeEditForm barrel re-export from forge/actions/index
  (imported directly by ForgeEntityActions)
- Strip forge/index.ts barrel to only actually-consumed exports
  (buildForgeProvider, ForgeIssue, ForgeCommit, ForgeFileChange,
  mapGithubPr)
- Remove ForgeTimelineSection/ForgeChecksSection from views barrel
  (imported directly by ForgeEntityDetailView)

packages/ui/src/components/views/forge/actions/index.ts

@@ -14,6 +14,5 @@ export { ForgeStateActions } from './ForgeStateActions';
 export { ForgeReviewActions } from './ForgeReviewActions';
 export { ForgeDraftToggle } from './ForgeDraftToggle';
 export { ForgeMetadataEditor } from './ForgeMetadataEditor';
-export { ForgeEditForm } from './ForgeEditForm';
 export { ForgeEntityActions } from './ForgeEntityActions';
 export { ForgeCreateIssueDialog } from './ForgeCreateIssueDialog';

packages/ui/src/components/views/forge/actions/useForgeLookup.ts

@@ -22,7 +22,7 @@ export interface ForgeLookupOption {
 }
 
 /** Resolve the dropdown option shape for a given provider/kind result. */
-export const toLookupOptions = (
+const toLookupOptions = (
   kind: ForgeLookupKind,
   users: ForgeUser[],
   labels: ForgeLabel[],

packages/ui/src/components/views/forge/index.ts

@@ -8,6 +8,4 @@
 export { ForgeMetadataChips } from './ForgeMetadataChips';
 export { ForgeCommitsSection } from './ForgeCommitsSection';
 export { ForgeFilesDiffSection } from './ForgeFilesDiffSection';
-export { ForgeTimelineSection } from './ForgeTimelineSection';
-export { ForgeChecksSection } from './ForgeChecksSection';
 export { ForgeEntityDetailView } from './ForgeEntityDetailView';