Feat v0.3.6 demo workflows + interactive demo

Four example workflow packages proving the engine end-to-end:
- Bug Report Triage: public entry, branch routing, SLA timer
- Employee Onboarding: Starlark automated stages, signoff gate
- Content Approval: multi-party signoff, revision cycle loop
- Webhook Notifier: http.post, connections fallback, delivery logging

Demo surface at /s/workflow-demo with cards, stage diagrams, Starlark
viewer, API examples, active/published status, and copyable public links.

Engine fixes: started_by in automated context, sla_seconds in package
installer, parseSnapshotStages for wrapped/legacy formats.

Platform fixes: extension SDK boot in base.html (Preact globals + boot()),
admin teams paginated response extraction, workflow adoption endpoint
(POST /teams/:teamId/workflows/:id/adopt), team-admin copyable link.

Review pass remains on roadmap for remaining UI polish.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/workflow/automated.go

@@ -73,10 +73,11 @@ func (e *Engine) processAutomatedStage(ctx context.Context, inst *models.Workflo
 	}
 
 	// Build context dict for the hook
-	ctxDict := starlark.NewDict(4)
+	ctxDict := starlark.NewDict(5)
 	_ = ctxDict.SetKey(starlark.String("instance_id"), starlark.String(inst.ID))
 	_ = ctxDict.SetKey(starlark.String("current_stage"), starlark.String(inst.CurrentStage))
 	_ = ctxDict.SetKey(starlark.String("workflow_id"), starlark.String(inst.WorkflowID))
+	_ = ctxDict.SetKey(starlark.String("started_by"), starlark.String(inst.StartedBy))
 
 	// Parse stage_data into Starlark dict
 	var dataMap map[string]interface{}