fix: remove false Content-Encoding gzip header causing 500 on child entity creates

[shaank0]

Summary

• Remove false Content-Encoding: gzip header from transformRequest in both AutotaskClient.ts and client-generator.ts. The header claimed gzip encoding but the body was plain JSON.stringify() — never actually compressed. This caused the Autotask API to return 500 Internal Server Error on child entity endpoints (POST /Quotes/{id}/Items, POST /Tickets/{id}/Notes) which strictly validate the encoding. Top-level endpoints were lenient and ignored the mismatch.
• Improve ServerError messages to include error details from responseData.errors for 500 responses. Previously, 500 errors showed only the generic "Internal Server Error" status text, making debugging extremely difficult.

Root Cause

In AutotaskClient.ts line ~414:

// BEFORE (broken):
transformRequest: [
    (data, headers) => {
        if (defaultPerformanceConfig.enableCompression && data) {
            headers!['Content-Encoding'] = 'gzip';  // Claims gzip...
        }
        return JSON.stringify(data);  // ...but sends plain JSON!
    },
],

// AFTER (fixed):
transformRequest: [
    (data) => {
        return JSON.stringify(data);
    },
],

The same bug existed in client-generator.ts and is fixed there too.

Impact

• All child entity creates (QuoteItems, TicketNotes, ProjectNotes, CompanyNotes) were broken with 500 errors
• Top-level creates (Quotes, Opportunities, Companies, Tickets) worked because those endpoints tolerated the header mismatch
• The decompress axios option for response decompression is unaffected — this only changes request encoding

Test plan

• npx tsc — compiles without errors
• Pre-existing test failures confirmed unrelated (same failures before and after this change)
• Verified fix works against live Autotask API — created 10 QuoteItems successfully after removing the header
• autotask-mcp should update its autotask-node dependency to this fix

Related

• wyre-technology/autotask-mcp#32 — workaround that passes enableCompression: false; can be simplified after this fix

🤖 Generated with Claude Code

[asachs01]

Closing in favor of PR #154 which extracts the error message improvement rebased cleanly onto main. The gzip removal is not included since main already properly compresses when enableCompression=true.