Implement complete nested todo tree web app MVP

This commit implements a fully functional self-hosted task decomposition engine with:

Backend (FastAPI + SQLite):
- RESTful API with full CRUD operations for projects and tasks
- Arbitrary-depth hierarchical task structure using self-referencing parent_task_id
- JSON import endpoint for seeding projects from LLM-generated breakdowns
- SQLAlchemy models with proper relationships and cascade deletes
- Status tracking (backlog, in_progress, blocked, done)
- Auto-generated OpenAPI documentation

Frontend (React + Vite + Tailwind):
- Dark cyberpunk theme with orange accents
- Project list page with create/import/delete functionality
- Dual view modes:
  * Tree View: Collapsible hierarchical display with inline editing
  * Kanban Board: Drag-and-drop status management
- Real-time CRUD operations for tasks and subtasks
- JSON import modal with validation
- Responsive design optimized for desktop

Infrastructure:
- Docker setup with multi-stage builds
- docker-compose for orchestration
- Nginx reverse proxy for production frontend
- Named volume for SQLite persistence
- CORS configuration for local development

Documentation:
- Comprehensive README with setup instructions
- Example JSON import file demonstrating nested structure
- API endpoint documentation
- Data model diagrams

frontend/src/utils/api.js

@@ -0,0 +1,58 @@
+const API_BASE = '/api';
+
+async function fetchAPI(endpoint, options = {}) {
+  const response = await fetch(`${API_BASE}${endpoint}`, {
+    headers: {
+      'Content-Type': 'application/json',
+      ...options.headers,
+    },
+    ...options,
+  });
+
+  if (!response.ok) {
+    const error = await response.json().catch(() => ({ detail: 'Request failed' }));
+    throw new Error(error.detail || `HTTP ${response.status}`);
+  }
+
+  if (response.status === 204) {
+    return null;
+  }
+
+  return response.json();
+}
+
+// Projects
+export const getProjects = () => fetchAPI('/projects');
+export const getProject = (id) => fetchAPI(`/projects/${id}`);
+export const createProject = (data) => fetchAPI('/projects', {
+  method: 'POST',
+  body: JSON.stringify(data),
+});
+export const updateProject = (id, data) => fetchAPI(`/projects/${id}`, {
+  method: 'PUT',
+  body: JSON.stringify(data),
+});
+export const deleteProject = (id) => fetchAPI(`/projects/${id}`, { method: 'DELETE' });
+
+// Tasks
+export const getProjectTasks = (projectId) => fetchAPI(`/projects/${projectId}/tasks`);
+export const getProjectTaskTree = (projectId) => fetchAPI(`/projects/${projectId}/tasks/tree`);
+export const getTasksByStatus = (projectId, status) =>
+  fetchAPI(`/projects/${projectId}/tasks/by-status/${status}`);
+
+export const getTask = (id) => fetchAPI(`/tasks/${id}`);
+export const createTask = (data) => fetchAPI('/tasks', {
+  method: 'POST',
+  body: JSON.stringify(data),
+});
+export const updateTask = (id, data) => fetchAPI(`/tasks/${id}`, {
+  method: 'PUT',
+  body: JSON.stringify(data),
+});
+export const deleteTask = (id) => fetchAPI(`/tasks/${id}`, { method: 'DELETE' });
+
+// JSON Import
+export const importJSON = (data) => fetchAPI('/import-json', {
+  method: 'POST',
+  body: JSON.stringify(data),
+});