JetBrains: accept Plugin Developer agreement

[avifenesh]

The v0.14.0 release workflow failed to publish the JetBrains plugin because the Plugin Developer agreement has not been accepted.

Error: Failed to upload plugin: Upload failed: You have not accepted the Plugin Developer agreement.

Action required: Visit https://plugins.jetbrains.com/intellij/io.agnix.jetbrains/page and accept the agreement, then re-run the JetBrains publish job.

[avifenesh]

This requires manual action: visit the JetBrains Marketplace and accept the Plugin Developer agreement. Once accepted, re-run the JetBrains publish step from the release workflow, or publish manually via the marketplace UI.

The workflow step uses ChrisCarini/intellij-platform-plugin-verifier-action followed by plugin upload - it should work once the agreement is in place.

[avifenesh]

Agreement accepted, plugin published to JetBrains Marketplace.