Add tag management system that allows users to create, edit, and delete
tags scoped to their organization, and assign them to projects for
better organization and filtering.
- Add tag and project_tag database schemas with Drizzle migration
- Add tRPC router for tag CRUD and project-tag assignment operations
- Add tag management page in Settings with color picker
- Add tag selector to project create/edit form
- Add tag filter to project list with localStorage persistence
- Display tag badges on project cards