feat: rename bugfix-ship/requirement-flow to short-ship/long-ship with shared ship records

short-ship and long-ship share one ship-id record under .pouch/ship/<id>/.
specifier writes PRDs into spec/; delivery-loop appends evidence pointers.
Old names stay as deprecation stubs so existing installs keep working.

skills/ship/templates/tasks.template.yaml

@@ -0,0 +1,11 @@
+shipId: <ship-id>
+tasks:
+  - id: T-01
+    title: <short title>
+    dependsOn: []
+    expected:
+      - <observable acceptance signal>
+    verification:
+      - <how to verify>
+    status: open
+    stopAt: null