feat(BT-002): add historical snapshot provider

docs/roadmap/ROADMAP.yaml

@@ -13,7 +13,6 @@ notes:
   - Pre-alpha policy: we may cut or replace old features without backward compatibility until alpha is declared.
   - Alpha migration policy: once alpha is declared, compatibility only needs to move forward; backward migrations are not required.
 priority_queue:
-  - BT-002
   - BT-001C
   - EXEC-001
   - EXEC-002
@@ -21,7 +20,9 @@ priority_queue:
   - DATA-001A
   - OPS-001
   - BT-003
+  - BT-002A
 recently_completed:
+  - BT-002
   - PORT-003
   - BT-003B
   - CORE-001D
@@ -43,9 +44,9 @@ states:
     - OPS-001
     - EXEC-001
     - EXEC-002
-    - BT-002
     - BT-003
     - BT-001C
+    - BT-002A
   in_progress: []
   done:
     - DATA-001
@@ -61,6 +62,7 @@ states:
     - EXEC-001A
     - BT-001
     - BT-001A
+    - BT-002
     - BT-003A
     - BT-003B
     - CORE-001A