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>

Services/DatabaseService.cs

@@ -148,6 +148,7 @@ public partial class DatabaseService
         }
         catch { /* already migrated */ }
         TryAddColumn(conn, "chains", "stream_error_info", "TEXT");
+        TryAddColumn(conn, "chains", "workflow_info", "TEXT");
         TryAddColumn(conn, "agents", "use_soul", "INTEGER NOT NULL DEFAULT 1");
         TryAddColumn(conn, "agents", "use_identity", "INTEGER NOT NULL DEFAULT 1");
         TryAddColumn(conn, "agents", "use_user_info", "INTEGER NOT NULL DEFAULT 1");