feat: RoutingWorkflow + LLM Router + Memory Activity

- Add RoutingWorkflow: generic state machine executor for WorkflowSpec
- Add LLM Router: natural language → WorkflowSpec generation
- Add RetrieveMemoryActivity: query poimen-memory for context
- Add activities: AnalyzeCode, SecurityScan, GenerateReport, Notify, etc.
- Add agent-prompts/router: LLM prompt documentation
- Extend starter with --route flag for routing workflows
- Remove orchestrator job (trigger via API/message instead)
- Clean up: move docs to Desktop, add .gitignore for *.md

.gitignore

@@ -0,0 +1,8 @@
+# Ignore markdown docs except agent-prompts
+*.md
+!agent-prompts/*.md
+!agent-prompts/**/*.md
+# Binaries
+starter
+worker
+poimen