feat: add integrate commits to parental branch section and wired UI

Introduce IntegrateCommitsSection to plan and apply commits from source to target branch
Wire the integration panel into GitView so users can run integrate flow from the current worktree

packages/ui/src/stores/useMultiRunStore.ts

@@ -167,6 +167,11 @@ export const useMultiRunStore = create<MultiRunStore>()(
                 startPoint: startPoint ?? null,
               });
 
+              const enrichedMetadata = {
+                ...worktreeMetadata,
+                createdFromBranch: startPoint ?? 'HEAD',
+              };
+
               // Session title format: groupSlug/provider/model (or groupSlug/provider/model/index for duplicates)
               const sessionTitle = count > 1
                 ? `${groupSlug}/${model.providerID}/${model.modelID}/${index}`
@@ -177,7 +182,7 @@ export const useMultiRunStore = create<MultiRunStore>()(
                 () => opencodeClient.createSession({ title: sessionTitle })
               );
 
-              useSessionStore.getState().setWorktreeMetadata(session.id, worktreeMetadata);
+              useSessionStore.getState().setWorktreeMetadata(session.id, enrichedMetadata);
 
               createdRuns.push({
                 sessionId: session.id,