fix(oauth): path-aware discovery 401 blocks connecting at mcp.memsprout.com/mcp

Adding memsprout as an MCP server in Claude Desktop or Claude Code via https://mcp.memsprout.com/mcp now completes successfully. The OAuth flow no longer silently aborts after the consent screen — the fix adds the three path-aware discovery endpoints (/.well-known/oauth-authorization-server/mcp, /.well-known/openid-configuration/mcp, /.well-known/oauth-protected-resource/mcp) required by spec-strict MCP clients that connect through a path-based server URL.