docs: document auto-recharge safeguards

[mintlify]

Adds an "Auto-recharge safeguards" subsection to the credits/auto-replenish docs:

• Automatic top-ups are capped at one per 5-minute window
• Auto-recharge pauses while balance is zero or negative
• Practical guidance: raise the per-recharge amount so a single top-up outlasts a 5-minute burst

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Project	Status	Preview	Updated (UTC)
x-corp	🟢 Ready	View Preview	Jun 13, 2026, 5:52 AM

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