[US2-5] Add active/inactive status toggle for tutors #42

User Story

As a tutor, I want to set my account to active or inactive, so that I can stop taking on new work without deleting my account or being blocked by outstanding-obligation checks.

Reviewer

@chotiwatt

Description

The original approach considered a full account deletion flow that would validate outstanding obligations (unresolved classes, unresolved balance) before allowing deletion. That approach is replaced: instead of deleting the account, tutors get a simple active/inactive status toggle. Setting status to inactive should not require passing validation checks — a tutor can go inactive at any time, including while they have outstanding classes or balances. Inactive status should stop the tutor from receiving new bookings/matches; existing obligations are unaffected and remain visible/resolvable.

Scope

• Add an active/inactive toggle accessible to an authenticated tutor for their own account.
• Persist and expose the tutor's status (active/inactive).
• Inactive tutors are excluded from new booking/match/search flows.
• No blocking validation is required to switch status in either direction.

Acceptance Criteria

• Given an authenticated tutor, when they set their status to inactive, then the status is saved without any outstanding-class or outstanding-balance check.
• Given a tutor is inactive, when students search or attempt to book, then that tutor does not appear as available.
• Given a tutor is inactive, when they set their status back to active, then they become available for new bookings again.
• Given a tutor has outstanding classes or an outstanding balance, when they toggle to inactive, then the toggle still succeeds (no rejection).

Out of Scope

• Account deletion.
• Outstanding-obligation validation/blocking logic.
• Student-side active/inactive status.
• Admin-initiated status changes.

Risk

• None