feat(accounts): add per-account model routing and clear WorkBuddy cooldowns

[caigee-cmd]

What changed

• Add per-account model aliases and optional enabled-model restrictions in the console and routing pool.
• Clear and persist a WorkBuddy account's cooldown after a successful daily check-in.

Validation

• go test ./...
• frontend npm run sync and npm run lint (Node 22)
• release-notes validation and git diff --check