Add agent-workflow skill skeleton

skills/agent-workflow/references/state-machine.md

@@ -0,0 +1,25 @@
+# Minimal state machine
+
+## States
+- planned
+- dispatching
+- in_progress
+- blocked
+- reviewing
+- done
+
+## Typical flow
+1. `planned`
+2. `dispatching`
+3. `in_progress`
+4. `reviewing`
+5. `done`
+
+## Failure shortcuts
+- `dispatching` + no worker trace within 10 minutes -> `blocked (launch failure)`
+- `in_progress` + ETA exceeded with no milestone -> `blocked (stalled)`
+
+## Notes
+- Keep the state machine small.
+- Avoid adding extra states unless repeated real-world failures demand them.
+- State changes should be backed by evidence, not optimism.