Add complete projects schema with timesheets support:
- projects.projects table with status, privacy settings
- projects.tasks table with Kanban support
- projects.timesheets table for Odoo-style time tracking
- projects.milestones table for project milestones
- projects.project_stages table for Kanban columns
- projects.project_members table for team management
Includes all necessary indexes and enums for performance.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
