Task Description

Implement Phase 5 of the LLM response routing plan by wiring resilient SignalR clients for both the Blazor web UI and the Consolonia console UI so downstream chat/dashboard features can subscribe to real-time task events.

Implementation Plan

• Add Microsoft.AspNetCore.SignalR.Client to the web/console projects, add DotnetAgents.Core references where needed, and introduce TaskHub client configuration (base URL → /taskHub).
• Define a shared TaskHub client contract (interfaces + payload helpers) inside DotnetAgents.Core so both frontends can rely on the same strongly typed events.
• Implement TaskHubService in DotnetAgents.Web with automatic reconnect, subscribe/unsubscribe helpers, lifecycle logging, and DI registration/startup/shutdown wiring.
• Implement ConsoleTaskHubService plus lightweight UI hooks (status text, connection lifecycle) so the console app also establishes and maintains a hub connection using the shared contract.
• Add guardrail tests for the new TaskHub client components, update the Phase 5 walkthrough/verification docs, and capture manual AppHost run logs showing successful hub connections.

Acceptance Criteria

• Web UI registers ITaskHubClient as a singleton, starts the hub connection on startup, and exposes typed events (TaskStatusChanged, TaskProgress, etc.).
• Console app starts the same hub client implementation (console-specific) and surfaces connection status without crashing if the hub is unavailable.
• Shared TaskHub contract + DTOs live in DotnetAgents.Core (no anonymous payloads or duplicated types in clients) and are referenced by both frontends.
• dotnet build + dotnet test succeed, and manual Aspire/AppHost run logs show clients connecting to /taskHub with no unhandled exceptions.

Testing Plan

• dotnet build DotnetAgents/DotnetAgents.slnx
• dotnet test DotnetAgents/DotnetAgents.Tests/DotnetAgents.Tests.csproj
• New unit tests covering TaskHub client event serialization/handling
• Manual AppHost run (dotnet run DotnetAgents/DotnetAgents.AppHost) to verify both clients log successful SignalR connections.

Implementation Notes

• Base hub URL should come from Aspire service discovery (services:agentapi:https:0) with fallback to AGENT_API_BASE_URL env var and https://localhost:7000 default for standalone console runs.
• Hook IHostApplicationLifetime (web) / Avalonia lifetime (console) to stop the hub gracefully on shutdown.
• Document new environment variable expectations and console usage updates inside docs/Phase5_Web_SignalR_Client_Walkthrough.md.

Related Issues/PRs

• LLM Response Routing Implementation Plan (Phase 5 section)