Why: the forced password gate still submitted an empty current password
after the backend began requiring it (current_required), locking every
account seeded with an initial password out of the workbench, and the
admin user panel had no client for the owner-confirmed recovery
proposal contract that replaced one-time key issuing (HTTP 410).
Evidence: npm test 300 passed; tsc -b && vite build ok; knip issues
54 <= baseline 55 (SELF).
Impact: mode-aware ChangePasswordGate with current-password input,
admin recovery proposal panel, owner-side account settings section,
recovery proposal client methods; no backend changes.
Refs: backend 8dfc223, b9c0a34; frontend #94
weichen