Add workflow-status telemetry view and make panel modes on-demand

Workflow-status: a new WorkflowProgressTracker singleton taps the
suppressed dynamic-workflow subagent events (those carrying
parent_tool_use_id) into per-session telemetry without altering the
existing guard; the snapshot is serialized into the new chains.workflow_info
column on FinalizeChain (ChainId-matched so a panel member of the same
session cannot clear it) and exposed via GET /api/sessions/{id}/workflow-status
(live -> persisted -> none). The header menu gains a 'Workflow-Status' entry
with a modal that live-polls every 2s while running and self-stops on close.

Panel on-demand: Fusion/MoA is now a transient per-request multiModelMode
flag (like plan/ultracode) instead of a persisted session column. Session
settings keep only the panel members + moa_layers; the mode <select> was
removed and the composer dropdown drives the mode per request.

Docs: ARCHITECTURE.md, ARCHITECTURE_QUICK.md and README.md updated for both
features plus the already-shipped z.ai/GLM provider, GLM 5.2+ effort
passthrough, web-search-prime MCP and the ultracode toggle.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Endpoints/ChatEndpoint.cs

@@ -56,7 +56,7 @@ public static class ChatEndpoint
 
         var remoteConn = remoteMgr.GetBySessionId(sessionId);
         var hasRemote = remoteConn != null;
-        var ctx = await chatService.PrepareContext(sessionId, userId, maxIterations, planMode: body.PlanMode, hasRemoteConnection: hasRemote, remoteOs: remoteConn?.OsVersion);
+        var ctx = await chatService.PrepareContext(sessionId, userId, maxIterations, planMode: body.PlanMode, multiModelMode: body.MultiModelMode, hasRemoteConnection: hasRemote, remoteOs: remoteConn?.OsVersion);
         if (ctx == null)
         {
             res.StatusCode = 400;