Implement Domain-Specific Policy Middleware Layer

[AnuMonachan]

Implement the domain-specific authorization middleware layer (the "Domain Authorization" optimization step from the architecture diagram) to handle context fetching and policy evaluation before reaching the route handlers.

Tasks

• Implement authorization middleware for chapter-assignment
• Implement authorization middleware for project
• Implement authorization middleware for users

[AnuMonachan]

SP4
merge code changes (ET - 2 hrs)
implement chapter middleware (ET - 4 hrs)
implement projects middleware (ET - 4 hrs)

SP5
merge code changes (ET - 1 hr)
implement users middleware (ET - 4 hrs)
review and test (ET - 3 hrs)
code review fixes (ET - 2 hrs)