feat(postgrest): Implement maxAffected method

[grdsdev]

Summary

• Implement maxAffected method equivalent to postgrest-js library
• Sets maximum number of rows that can be affected by update and delete operations
• Adds handling=strict and max-affected={value} to Prefer header

Implementation Details

• Added maxAffected(int value) method to PostgrestTransformBuilder class
• Preserves existing Prefer headers when adding maxAffected
• Supports method chaining with other transform methods
• No runtime validation - relies on documentation for proper usage guidance

Usage Examples

// Update with max affected rows limit
supabase.from('users').update({'active': false}).eq('status', 'inactive').maxAffected(5);

// Delete with max affected rows limit  
supabase.from('users').delete().eq('active', false).maxAffected(10);

// Method chaining
supabase.from('users').update({'status': 'INACTIVE'}).eq('id', 1).maxAffected(1).select();

Test Coverage

• ✅ Unit tests for method availability and chaining
• ✅ Integration tests validating HTTP headers using custom client
• ✅ Tests for preserving existing Prefer headers
• ✅ All existing tests continue to pass

Notes

• Requires PostgREST v13 or higher
• Only effective with PATCH and DELETE operations (documented in method docs)
• When limit is exceeded, PostgREST will return an error

🤖 Generated with Claude Code