feat: land superpaper v1 notes scaffold

Add the ledger schema, class router, lint codes, ingest/build
pipeline, and three work-tree examples: align derivation,
superfig delegation, and supertensor delegation.

assets/ledger.example.yaml

@@ -0,0 +1,24 @@
+schema: superpaper.ledger/v1
+retired_ids: []
+paper:
+  id: "example"
+  title: ""
+  authors: []
+  notes_language: zh
+  source:
+    kind: excerpt
+coverage:
+  mode: excerpt
+  sections_in: []
+  sections_skipped: []
+questions: []
+claims: []
+definitions: []
+assumptions: []
+lemmas: []
+symbols: []
+derivations: []
+figures: []
+evidence: []
+terms: []
+source_assets: []