docs: improve docs config, error codes, and navigation

[marioalvial]

Summary

• Add Mintlify contextual menu with copy, AI tools, and MCP integration options
• Expand common error codes from 5 to 18, covering all customer-facing exceptions from ktor-extension and development-utils
• Remove totalMatches and includeTotalMatches from pagination docs, quickstart, and snippet
• Restructure API Reference sidebar: pull Documents and Funding instructions into their own top-level groups

Test plan

• mint dev renders correctly
• Contextual menu appears in page header with copy/view/AI options
• API Reference sidebar shows Accounts (with UBOs nested), Documents, Funding instructions as separate groups
• Error codes table displays all 18 entries grouped by HTTP status
• Pagination page, quickstart, and snippet no longer reference totalMatches

[mintlify]

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Project	Status	Preview	Updated (UTC)
tracefinance	🟢 Ready	View Preview	Apr 15, 2026, 12:38 AM

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