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/useAgentGroupsStore.ts

@@ -9,6 +9,7 @@ import type { WorktreeMetadata } from '@/types/worktree';
 import { listWorktrees, mapWorktreeToMetadata } from '@/lib/git/worktreeService';
 import type { Session } from '@opencode-ai/sdk/v2';
 
+// LEGACY_WORKTREES: legacy worktree root inside project.
 const OPENCHAMBER_DIR = '.openchamber';
 
 const resolveProjectDirectory = (currentDirectory: string | null | undefined): string | null => {