feat: add OPC (One Person Company) management system with Kanban board

Phase 1 MVP implementation:
- PostgreSQL database schema for tasks, agents, executions, time tracking
- Backend API: task CRUD, agent management, automatic time tracking
- Frontend: Kanban board with drag-and-drop (Parking Lot → In Progress → Done)
- Task modal for creating/editing tasks with tags, priority, assignee
- 3 core agents seeded: PM, CTO, COO
- Agent approval workflow: CxO level requires approval, others auto-execute
- Automatic time tracking: starts on in_progress, stops on done
- RBAC integration: OPC page accessible to admin/member roles

Features:
- Drag-and-drop tasks between columns
- Assign tasks to humans or AI agents
- Priority badges (low, medium, high, urgent)
- Tags and due dates
- Task history tracking
- Time entry tracking with automatic timer
- Agent execution records with approval workflow

Next steps:
- Initialize OPC database on NAS
- Implement agent executor service
- Add WebSocket for real-time updates
- Add email notifications
- Add PDF invoice generation

dashboard/frontend/src/components/Sidebar.svelte

@@ -20,6 +20,7 @@
     { id: "dashboard", label: "Overview", icon: "grid" },
     { id: "info-engine", label: "Info Engine", icon: "sparkles" },
     { id: "litellm", label: "LiteLLM", icon: "bolt" },
+    { id: "opc", label: "OPC", icon: "kanban" },
     { id: "docker", label: "Docker", icon: "box" },
     { id: "files", label: "Files", icon: "folder" },
     { id: "terminal", label: "Terminal", icon: "terminal" },
@@ -243,6 +244,8 @@
       <svg class="w-[18px] h-[18px]" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.8"><path stroke-linecap="round" stroke-linejoin="round" d="M8 9l3 3-3 3m5 0h3M5 20h14a2 2 0 002-2V6a2 2 0 00-2-2H5a2 2 0 00-2 2v12a2 2 0 002 2z" /></svg>
     {:else if icon === "shield"}
       <svg class="w-[18px] h-[18px]" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.8"><path stroke-linecap="round" stroke-linejoin="round" d="M9 12l2 2 4-4m5.618-4.016A11.955 11.955 0 0112 2.944a11.955 11.955 0 01-8.618 3.04A12.02 12.02 0 003 9c0 5.591 3.824 10.29 9 11.622 5.176-1.332 9-6.03 9-11.622 0-1.042-.133-2.052-.382-3.016z" /></svg>
+    {:else if icon === "kanban"}
+      <svg class="w-[18px] h-[18px]" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.8"><path stroke-linecap="round" stroke-linejoin="round" d="M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h2a2 2 0 002-2V7a2 2 0 00-2-2zm8 0h-2a2 2 0 00-2 2v8a2 2 0 002 2h2a2 2 0 002-2V7a2 2 0 00-2-2z" /></svg>
     {:else if icon === "music"}
       <svg class="w-[16px] h-[16px]" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.8"><path stroke-linecap="round" stroke-linejoin="round" d="M9 19V6l12-3v13M9 19c0 1.105-1.343 2-3 2s-3-.895-3-2 1.343-2 3-2 3 .895 3 2zm12-3c0 1.105-1.343 2-3 2s-3-.895-3-2 1.343-2 3-2 3 .895 3 2z" /></svg>
     {:else if icon === "play"}