Job-alert two-lane model

Choose exactly one lane:

• Anonymous visitors use board.jobAlerts.*: double opt-in, then an HMAC manage token from email.
• Signed-in users use board.me.alerts.*: bearer-authenticated CRUD, active immediately, with up to 10 alerts per user.

Both lanes are available only when board.context() reports features.jobAlerts.

Anonymous lane: subscribe and confirm

subscribe requires consent and deliberately returns the same submitted response for new and existing addresses. confirm always resolves; its status owns the landing-page branch.