refactor: centralize API error handling in ky client

[Paveltarno]

Description

This PR centralizes API error handling logic by implementing a beforeError hook directly in the ky HTTP client. Previously, every API method had to manually wrap calls and invoke formatApiError. Now, all API errors are automatically caught and formatted by the base client, eliminating boilerplate and ensuring consistent error handling across the codebase.

Related Issue

Addresses refactoring discussed in #112: #112 (comment)

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Other (please describe):

Changes Made

• Moved formatApiError function to be internal within base44-client.ts (no longer exported)
• Implemented handleApiErrors hook using ky's beforeError mechanism to automatically format all API errors
• Updated base44Client configuration to include the new error handling hook
• Removed formatApiError export from index.ts
• Simplified agent/api.ts by removing manual error handling and throwHttpErrors: false flags
• Simplified entity/api.ts by removing manual error handling while preserving special 428 status code logic
• Removed tests/core/errors.test.ts as formatApiError is now an internal implementation detail
• Updated JSDoc comments to reflect automatic error handling behavior

Testing

• I have tested these changes locally
• I have added/updated tests as needed
• All tests pass (npm test)

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (if applicable)
• My changes generate no new warnings
• I have updated AGENTS.md if I made architectural changes

Additional Notes

This refactoring reduces boilerplate code by 13 net lines (83 additions, 96 deletions) while improving maintainability. The error handling behavior remains functionally identical from the consumer's perspective - all API errors are still caught and formatted into readable error messages. The 428 status code special handling in syncEntities is preserved using ky's HTTPError type.

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_{🤖 Generated by Claude | 2026-01-27 21:45 UTC}

[github-actions]

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  "dependencies": {
    "base44": "npm:@base44-preview/cli@0.0.22-pr.135.f4b78d8"
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