[Feature]: Configurable Spending Cap Period for PAYG API Keys (Daily / Weekly / Monthly)

[abnershang]

Hi ZenMux team,

Currently, PAYG API keys support a spending cap, but it's a single lifetime/total limit. For production use, this isn't granular enough to control burn rate or contain runaway usage from bugs, loops, or compromised keys.

Request

Add a cap period selector alongside the spending cap amount, with options:

• Daily — resets every 24h (UTC or user tz)
• Weekly — resets every 7 days
• Monthly — resets on calendar month or rolling 30d

Why it matters

1. Blast radius control — a leaked or misbehaving key can't drain more than one period's budget before auto-cutoff.
2. Budget predictability — teams can align API spend with monthly finance cycles without manual top-ups.
3. Per-key experimentation — devs can issue short-lived daily-capped keys for tests/agents without risking the master budget.

Ideal UX

• Dropdown: Cap period: [None | Daily | Weekly | Monthly]
• Numeric field: Cap amount: $___
• Display: Spent this period: $X.XX / $Y.YY · resets in Nd Nh

Nice-to-haves

• Webhook/email alert at 80% of period cap
• Per-key override of account-level defaults

Thanks — this would make PAYG keys much safer to hand to autonomous agents.