Document JetBrains Marketplace listing and first-upload values

[redcatbear]

Situation

The repository has an Apache 2.0 license and public source code, but it does not document the exact values needed for the first JetBrains Marketplace upload: vendor, license, source-code URL, tags, release channel, privacy/data statement, and other listing fields.

Because the first plugin publication must be uploaded manually, the project needs a project-owned checklist so the uploader does not invent these values during the Marketplace UI flow.

Relevant docs:

• https://plugins.jetbrains.com/docs/marketplace/uploading-a-new-plugin.html
• https://plugins.jetbrains.com/docs/marketplace/best-practices-for-listing.html

Out-of-Scope

• Creating the JetBrains account or vendor profile.
• Accepting JetBrains Marketplace legal agreements or trader/non-trader declarations.
• Performing the actual first manual upload.
• Writing marketing copy unrelated to the plugin behavior.

Acceptance Criteria

1. A Marketplace publication checklist exists in project documentation.
2. The checklist records the intended vendor, license, source-code URL, tags, release channel, and visibility setting.
3. The checklist includes a concise privacy/data statement for the plugin behavior, including whether the plugin collects telemetry or sends project content anywhere.
4. The checklist links to the exact signed ZIP artifact that should be uploaded for the first publication.
5. The checklist names the project-controlled metadata that must be changed in source before a Marketplace listing can be updated by a new upload.