feat: migrate schema to DATE type, add test infrastructure

- Migrate due_date/next_occurrence columns from TIMESTAMPTZ to DATE
- Update serializeRow() to distinguish DATE vs TIMESTAMPTZ serialization
- Simplify frontend date parsing (no more timezone workarounds)
- Add Vitest + Testing Library test infrastructure
- Add initial date parsing/formatting unit tests
- Update package.json with dev dependencies (vitest, testing-library, jsdom)

.hermes/plans/vixtix-build.md

@@ -0,0 +1,47 @@
+# VixTix Implementation Plan
+
+## Architecture
+- Next.js 16 App Router (TypeScript + Tailwind)
+- PostgreSQL database (Docker container, port 5433)
+- Drizzle ORM for database access
+- RESTful API routes under `/app/api/`
+- Multi-stage Docker build with PostgreSQL
+
+## Database Schema
+- **projects**: id, name, description, color, sort_order, created_at, updated_at
+- **tasks**: id, project_id (FK), title, description, completed, priority (low/medium/high/urgent), due_date, status (todo/in_progress/done), parent_task_id (FK, self-ref), recurrence_rule (daily/weekly/biweekly/monthly/yearly/none), recurrence_interval, next_occurrence, sort_order, created_at, updated_at
+- **Recurring tasks**: Handled inline in tasks table. When completed, if recurrence_rule != 'none', create new task with same data, next_occurrence as new due_date, and increment sort_order.
+
+## API Routes
+- `GET /api/tasks?project=&search=&status=&priority=&due_before=&due_after=&completed=` — list with filters
+- `POST /api/tasks` — create task
+- `PUT /api/tasks/[id]` — update task
+- `DELETE /api/tasks/[id]` — delete task
+- `PATCH /api/tasks/[id]/done` — toggle completion (handles recurrence)
+- `GET /api/projects` — list projects
+- `POST /api/projects` — create project
+- `PUT /api/projects/[id]` — update project
+- `DELETE /api/projects/[id]` — delete project
+- `GET /api/kanban` — tasks grouped by status
+
+## Frontend Views
+1. **Sidebar**: Projects list (click to filter), New Task button, view switcher (List/Kanban/Calendar)
+2. **List View**: Filterable task list with search, sort by due date/priority. Click task opens detail panel.
+3. **Kanban Board**: Three columns (Todo/In Progress/Done). Click to move between statuses.
+4. **Calendar View**: Monthly grid showing tasks on due dates. Click date to create task.
+5. **Detail Panel**: Right-side panel for viewing/editing task details (title, description, project, priority, due date, recurrence, subtasks).
+6. **New Task Modal**: Quick add from header.
+7. **Recurring Task Modal**: Configure recurrence rule and interval.
+
+## UI Design
+- Clean, modern productivity app aesthetic
+- Dark sidebar (#1a1a2e), white content area
+- Color-coded priority badges (red=urgent, orange=high, yellow=medium, green=low)
+- Project color indicators
+- Responsive layout
+
+## Docker
+- Multi-stage build: builder + runner
+- PostgreSQL container on port 5433 (avoiding conflicts)
+- App on port 3070
+- Docker Compose for orchestration