fix(link): send QR code custom options as multipart/form-data

[jaredwray]

Problem

Creating a QR code with custom options (title, backgroundColor, color, size, logo) failed against the Hyphen API. The previously-skipped integration test confirmed it (see #133), and I reproduced it against the live API:

Error: Fetch failed with status 400

Root cause

The QR create endpoint in apix (POST /organizations/:org/link/codes/:code/qrs) consumes multipart/form-data — fastify/multipart is registered with attachFieldsToBody: true, the schema declares consumes: ['multipart/form-data'], each field is read as body[key].value, and logo is a file (isFile: true).

The SDK's createQrCode, however, sent the options as a JSON body with content-type: application/json. Schema validation expected each field to be an object ({ value }), so a JSON string like { "title": "..." } was rejected with HTTP 400.

This is why QR creation without options worked (the body serialized to {}, which passes validation) but with options always failed — exactly the reported symptom.

Fix (SDK only)

createQrCode now builds a multipart/form-data request:

• title, backgroundColor, color, size are sent as form fields.
• logo (a base64 string) is decoded and appended as a file upload, matching the API's isFile expectation.
• The JSON content-type header is dropped so the multipart boundary is set automatically by fetch.
• When no options are provided, the SDK falls back to an empty JSON body, because the API rejects an empty multipart payload with {"message":"body must be object"} — this preserves the existing default-QR behavior.

The public API is unchanged: callers still pass CreateQrCodeOptions exactly as before. No apix changes are required — the SDK simply now conforms to the existing multipart contract.

Verification

• Re-enabled the previously skipped custom-options integration test; it now passes against the live API.
• Added unit coverage for both the multipart (with options) and empty-JSON (no options) paths, asserting the body shape and content-type handling.
• pnpm test: 233 passed, 100% coverage (statements/branches/functions/lines).
• pnpm build: succeeds with no type errors.

Closes #133

https://claude.ai/code/session_01Taskt9xiXWzsGVmKPbPpnj

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Generated by Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (54f15b5) to head (6de740b).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #137   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            8         8           
  Lines          477       492   +15     
  Branches        95       101    +6     
=========================================
+ Hits           477       492   +15     

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