Dashboard Manage Resources now shows only active workers/projects/teams
by default. Inactive items are hidden behind a collapsible "Show X
Inactive" button — faded at 50% opacity. Tab badges show active counts.
Also adds start_date and end_date fields to Project model (optional).
Dates display under the project name in the resource list.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>