Inspector auth debug view shows incorrect metadata URL path in details

[pcarleton]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Input a server url with OAuth or PRM metadata not at the root (e.g. https://mcp-oauth-ex2.val.run/mcp)
2. Open the auth debug flow, click through oauth metadata discovery
3. Expand "oauth metadata sources"
4. Witness https://mcp-oauth-ex2.val.run/.well-known/oauth-protected-resource listed as where it found the metadata

Expected behavior
A clear and concise description of what you expected to happen.

Should show https://mcp-oauth-ex2.val.run/.well-known/oauth-protected-resource/mcp

Logs
If applicable, add logs to help explain your problem.

Additional context
Add any other context about the problem here.