[calvin-www]

Students need to use contact privacy without deciding whether to expose someone’s email and phone themselves. Add getVisibleProfile(ctx, tx, currentUser, record): it returns a profile with contacts only for self or shared-ride peers, using the supplied transaction. Guests receive no contacts, and a failed permission lookup returns an error and no profile. Keep the copying helper internal so ride results retain one permission lookup for all owners and riders.

Rename Actor to CurrentUser, use requireSignedInUser for identity extraction, and give conversion and error helpers clearer verbs. Update comments and existing tests. Student operation stubs remain intact.

Add HELPERS.md and link it from the README, matching the revised Google Doc. The guide explains request identity, stored records, prepared results, and automatic contact permissions with concrete examples. It omits the general tutorials on types, structs, transactions, and sqlc.

Validation: go test -race -count=1 ./..., go vet ./..., go build ./..., formatting, and git diff --check passed. New helper tests cover self, shared-ride peers, unrelated profiles, guests, and permission-query failures. Unfinished student operations retain their existing test skips.

Companion reference implementation: https://github.com/chu-andrew/carpool4/pull/3