Auth-failure detection substring-matches server error text on the MCP tool-call path

[Aaronontheweb]

Part of #2058. Design: openspec/changes/mcp-tool-outcome-receipts/design.md (D4).

Problem

McpClientManager.ReportToolFailure runs IsAuthFailureMessage over the text of an isError: true tool result and, on a substring match (unauthorized, forbidden, token expired, ...), moves the server to AuthFailed with the remedy Run: netclaw mcp auth <name>.

• A normal business error such as {"error":"Request failed: 403 Forbidden"} from a tool that proxies a REST API trips the check. For a server that does not use OAuth, netclaw mcp auth is the wrong remedy. A false authentication_failed alert fires, and netclaw mcp list and doctor report auth failed until the next invocation reconnects for nothing.
• A real credential failure on a server that does not use OAuth is not detected. A static bearer or API key that expires mid-session comes back as HTTP 401 on every tool call, but nothing marks the server, so netclaw mcp list keeps reporting Connected.

The rule must not read header names. A server can authenticate with any header. The daemon already knows whether it uses OAuth for a server: it holds OAuth tokens for it, or the SDK reported a Bearer challenge.

Expected

• A 401 on a tool call or a catalog refresh moves the server to AuthFailed. The remedy follows the OAuth state, not the config shape: netclaw mcp auth when the daemon holds OAuth tokens for the server or the failure is an OAuth challenge; "check configured credentials or headers" otherwise.
• A 403 on a tool call does not change the server state. It is an access_denied result only.
• Tool-declared error text demotes a server only when the daemon holds OAuth tokens for it. Any other server stays Connected, with the Warning log unchanged.
• The connect path uses the same rule. A bare 401 or 403 at initialize with no tokens and no challenge is AuthFailed with the credentials remedy, not Unreachable.
• CreateUnavailableException and netclaw doctor read the remedy from the published status instead of a fixed string or a scheme test of their own.

Tests

• HTTP server with an X-Api-Key header, no tokens; tool call throws 401. AuthFailed; message names credentials or headers; no netclaw mcp auth; next call reconnects.
• HTTP server with stored OAuth tokens; tool call throws 401. AuthFailed; remedy names netclaw mcp auth.
• HTTP server, no tokens; tool call throws the SDK's Bearer-challenge McpException. AuthFailed; remedy names netclaw mcp auth.
• HTTP server; tool call throws 403. Stays Connected.
• HTTP server, no headers, no tokens; isError: true with expired-token text. Stays Connected.
• HTTP server with stored tokens; isError: true with expired-token text. AuthFailed (current behavior).
• Static-header server and stdio server; isError: true with Forbidden text. Stay Connected.