#65 FTX-65: One-click confirm interstitial

GET /a/click/{token} renders confirm form without consuming (EV-AW-4; also fixes TemplateResponse(request=None) 500s); POST consumes atomically (UPDATE WHERE consumed_at IS NULL RETURNING) + apply_action same transaction; refused at mint AND consume when justification required (AC-8). Double-POST race test. Phase 6.