Implement protocol fee aggregation and admin claim to treasury

[NueloSE]

Summary

Implements protocol fee aggregation and admin claim functionality as described in #348:

• Adds an internal unclaimed_fees accumulator to track protocol fees (1% of each donation).
• Updates donate to deduct and accumulate protocol fees separately from pool allocations.
• Implements claim_protocol_fees allowing protocol admins to transfer all accumulated fees to a treasury address via the token contract.
• Ensures fee tracking is fully isolated from pool allocations and student claims.
• Adds and updates comprehensive tests for all new logic.
• Ensures build, tests, and formatting requirements are satisfied.

Acceptance Criteria:

• Fee tracking is isolated from pool allocations.
• Admins can claim all accumulated fees to a treasury address.
• Project builds, tests pass, and code is formatted.

Closes

close #348