feat: add streamable HTTP transport, OAuth, and remote template support

[hashemix]

📌 Summary

Align the action with the latest mcp-discovery CLI (v0.3.x): add streamable HTTP transport + OAuth authentication support, remote template fetching, and fix several invocation bugs.

🔍 Related Issues

• Follows feat!: add streamable HTTP transport and OAuth authentication support mcp-discovery#37 (streamable HTTP transport + OAuth)
• Follows feat: add remote template fetching, template folders, and user-defined partials mcp-discovery#39 (remote template fetching)

✨ Changes Made

• Add inputs: url, header, client-id, client-secret, scope, redirect-uri, grant, template-url, cache-dir
• Make mcp-launch-command optional (mutually exclusive with url)
• Rewrite the run step to use a bash array instead of eval
• Pass --filename only for create/update (fixes print command)
• Update README inputs table and add streamable HTTP, OAuth, and remote-template examples

💡 Additional Notes

Non-breaking for the action (all new inputs optional, defaults preserved). No major version bump required.