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>

wwwroot/js/api.js

@@ -60,10 +60,12 @@ function apiMe() { return _get('/api/auth/me', null); }
 
 // ── Chat API ──
 
-function apiChat(content, sessionId, signal, planMode, ultracode) {
+function apiChat(content, sessionId, signal, planMode, ultracode, multiModelMode) {
   var payload = { content: content, sessionId: sessionId };
   if (planMode) payload.planMode = true;
   if (ultracode) payload.ultracode = true;
+  // Panel-Modus ist on-demand pro Anfrage (transient): nur fusion/moa durchreichen.
+  if (multiModelMode === 'fusion' || multiModelMode === 'moa') payload.multiModelMode = multiModelMode;
   return fetch('/api/chat', { method: 'POST', headers: _jsonHeaders, body: JSON.stringify(payload), signal: signal });
 }
 
@@ -124,6 +126,10 @@ function apiGetPayloadPreview(sessionId, planMode) {
   return _get(url);
 }
 
+function apiGetWorkflowStatus(sessionId) {
+  return _get('/api/sessions/' + sessionId + '/workflow-status');
+}
+
 function apiIsStreaming(sessionId) { return _get('/api/sessions/' + sessionId + '/streaming'); }
 function apiGitStatus(sessionId) { return _get('/api/sessions/' + sessionId + '/git-status', null); }