Named user credentials for DeepSeek Harness

Key features

• The tools register into the host tool registry, so every agent preset sees them.
• The settings page mounts its own Typert Remote contribution through the public ctx.remote.$mount seam — no api/remotes edit needed.
• The host service is a TypertRemoteService
• the gateway discovers its @Remote methods dynamically (SRC markers), so no code generation step is required to deploy.
• Stock-upstream notethe upstream api/remotes forwarded-event allowlist does not include credential-manager/updated, so the settings page does not receive live push invalidations from other surfaces