Fix fee validation, dispute persistence, and analytics capacity

[reactjay]

Summary

• Reject enabled fee configurations with a zero minimum fee, and document deposit, withdrawal, and admin collection fee behavior.
• Persist disputes with sequential IDs and update stored records through their lifecycle.
• Enforce analytics capacity using the stored summary count and avoid writing before summary validation completes.

Fixes #235
Fixes #236
Fixes #237
Fixes #239

Verification

• Added regression coverage for enabled zero-minimum fees, dispute persistence, and capacity count stability.
• git diff --check passed. Cargo tests could not be run because cargo is unavailable in the environment.

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