fix: wait for publish operation to complete before reporting success

[DanielSinclair]

Summary

submit() previously fired the publish request and returned immediately after receiving a 202 Accepted, without polling the publish status endpoint to verify the operation completed. The getPublishStatus() method existed but was never called from the submit flow.

This meant async publish failures were silently ignored and the extension remained as a draft. The following error codes would go undetected:

• NoModulesUpdated — no changes since last submission
• InProgressSubmission — another submission already under review
• SubmissionValidationError — submission validation failures
• ModuleStateUnPublishable — extension has invalid modules
• UnpublishInProgress — extension is being unpublished
• CreateNotAllowed — can't create new extension

Changes

• submit() now calls waitForPublish() after publish(), polling getPublishStatus() until the operation reaches Succeeded or Failed
• Mirrors the existing waitForUpload() pattern and Microsoft's reference implementation (10 retries, 5s intervals)
• Test updated to assert publishStatus.status === "Succeeded"

Test plan

• Verify integration test passes with pnpm dlx @plasmohq/mystic-box test-zip 0.0.8 + valid key.json
• Verify failed publishes throw with the actual Microsoft error message
• Verify timeout after max retries throws "Publish operation timed out"