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/main.go

@@ -562,6 +562,8 @@ func main() {
 				teamScoped.PATCH("/workflows/:id/stages/reorder", teamWfH.ReorderTeamWorkflowStages)
 				teamScoped.POST("/workflows/:id/publish", teamWfH.PublishTeamWorkflow)
 				teamScoped.POST("/workflows/:id/clone", teamWfH.CloneTeamWorkflow)
+				teamScoped.POST("/workflows/:id/adopt", teamWfH.AdoptTeamWorkflow)
+				teamScoped.GET("/workflows/available", teamWfH.ListGlobalWorkflows)
 				teamScoped.GET("/workflows/:id/versions/:version", teamWfH.GetTeamWorkflowVersion)
 
 				// Team workflow instances + assignments (v0.3.2)