feat(claude): set plugin display name to ReadMe

[minhthanhdang]

🚥 Follow-up to RM-18821

🧰 Changes

• The plugin directory listing now shows "ReadMe" instead of the auto-filled "Readme".
• Install name stays readme, so nothing changes for existing installs.

🧬 QA & Testing

• claude plugin validate --strict passes for the plugin and the marketplace.

[greptile-apps]

Confidence Score: 5/5

[Low risk] Updates a plugin metadata display name.

The PR appears safe to merge; no concrete break was found.

_{Reviews (1) · Last reviewed commit: "feat(claude): set plugin display name to..."}