docs(work): scaffold sandcastle-subscription-auth-v1 epic

docs/work/_state.json

@@ -1,5 +1,5 @@
 {
-  "updated_at": "2026-05-13T07:05:55.913Z",
+  "updated_at": "2026-05-13T07:27:04.538Z",
   "epics": {
     "agent-workflow-docs-v1": {
       "status": "done",
@@ -382,6 +382,20 @@
         }
       }
     },
+    "sandcastle-subscription-auth-v1": {
+      "status": "in-progress",
+      "title": "Sandcastle subscription auth as primary flow",
+      "stories": {
+        "01-subscription-first": {
+          "status": "in-progress",
+          "title": "Subscription-first dispatch — mount ~/.claude, install claude CLI, docs",
+          "ac_total": 8,
+          "ac_completed": 0,
+          "depends_on": [],
+          "blocks": []
+        }
+      }
+    },
     "visual-regression-v1": {
       "status": "done",
       "title": "Visual regression v1 — Playwright screenshot infrastructure",
@@ -435,6 +449,12 @@
       }
     }
   },
-  "ready": [],
+  "ready": [
+    {
+      "epic": "sandcastle-subscription-auth-v1",
+      "story": "01-subscription-first",
+      "title": "Subscription-first dispatch — mount ~/.claude, install claude CLI, docs"
+    }
+  ],
   "blocked": []
 }