Add Projects (tag) management and ticket→project association

[AstroMen]

Motivation

• Provide a categorization/tag (project) for tickets so each ticket belongs to a project (e.g. department or daily work).
• Allow admins to manage those project tags (create/update/delete) while members can only view them.
• Surface project selection in the UI when creating/editing tickets and show project information on ticket cards.

Description

• Added Project model and relationship, and made Ticket.project_id required with a Project relationship. (apps/dashboard_api/src/models/entities.py)
• Implemented new CRUD API endpoints under /projects with admin-only mutations and viewable by all authenticated users, and added project validation to ticket create/update/list endpoints. (apps/dashboard_api/src/api/projects.py, apps/dashboard_api/src/api/tickets.py)
• Created Alembic migration 0003_projects_table_and_ticket_project to create projects, insert default General, backfill existing tickets to that project, and add the foreign key constraint. (apps/dashboard_api/alembic/versions/0003_projects_table_and_ticket_project.py)
• Extended Pydantic schemas with project_id on ticket schemas and new ProjectCreate/ProjectUpdate/ProjectOut schemas. (apps/dashboard_api/src/schemas/common.py)
• Registered the projects router in the main app. (apps/dashboard_api/src/main.py)
• Frontend: added Projects nav link and a new /projects page for management with admin CRUD and member read-only behavior, updated tickets list and ticket edit pages to select/show project, and adjusted agents page to hide admin controls from members. (apps/dashboard_web/app/*)
• Updated smoke tests to create a project and include project_id when creating tickets. (apps/dashboard_api/tests/test_api_smoke.py)

Testing

• Ran API smoke tests with PYTHONPATH=apps/dashboard_api pytest apps/dashboard_api/tests/test_api_smoke.py, and all tests passed.
• Launched the web dev server with npm --prefix apps/dashboard_web run dev -- --hostname 0.0.0.0 --port 3000 and verified the new Projects page visually (screenshot captured).

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Codex Task