feat: zipped packages, target set, checklists, audit fixes and a stress test

Features for the next six months (accessible HTML export, paperpack and
Lode on packages, the personal bundle):

- Zipped packages: the oracle writes and reads `.sct.zip` archives under
  the rules of spec/12 §12.2; validate.py and load.py accept them; a
  byte-identical zip of the tiny package joins the fixtures, and two
  broken archives (traversal, symbolic link) join fixtures/invalid.
- The target set of targeted F3 (spec/08 §8.10) is computed by the
  oracle and pinned by vectors/targets.jsonl under each digit rule; the
  rule now covers cells as well as sentences and the leaves of anchored
  containers, and defines a node's section.
- scienting-checklist/1 (provisional): a conformance check of an export,
  covered by a receipt as ["checklist", id, hash] (spec/08 §8.11), with a
  WCAG 2.1 AA fixture and its receipt.
- QA reports are signed like receipts (spec/08 §8.9).
- A `description` annotation body with role alt or long, so an
  accessible export can find a confirmed figure description; the layer
  fixture carries one, and the store's body-kind constraint allows it.
- scienting-spot-check/1, the seed payload, is registered with a schema.
- exercise, submission and grade are provisional until a course has
  used them.

Audit fixes, each with a vector or a broken package where one was
missing:

- Folder packages: symbolic links are refused on validate and load,
  manifest paths must not collide under case folding, listed files are
  matched by exact name, files are hashed in chunks under a size limit.
- Files are compared byte for byte, so CR LF, a byte order mark, NaN,
  a lone surrogate or invalid UTF-8 is refused instead of translated;
  integers beyond 2^53 are read as doubles, as canonical JSON writes them.
- Receipts: signature.key must equal by and the key must be valid when
  signed; a qa receipt's nodes must be the sample at the original's
  hashes, its scope must name qa.of, its errors must be sampled nodes;
  statuses are computed once, iteratively, so chains of spot-checks
  hundreds deep settle; Base64 and manifest shape errors become refusals
  instead of tracebacks; counts and the fidelity of roster-less packages
  are recomputed.
- The gate enforces rule 11 of spec/11 §11.4: changed nodes are
  validated against the node schema and the references between nodes
  are checked, so a set to a bad value, an insert with unknown
  properties or a delete of a referenced header cell is refused; a
  relabel to null drops the label; a reclassify drops foreign
  attributes; a split strips whitespace across runs; ids.jsonl order
  follows spec/04 §4.4 in every state; a move after itself is refused.
- Anchors: the relabel rule requires that nothing else changed below the
  node; an alias chain ending in a deletion no longer crashes resolve.
- Notation: a script after an empty group applies to the previous atom
  ({}^{14}C); letters are defined by Unicode block in spec/05 §5.4 and
  the oracle; \left) is complex.
- Page fingerprints delete whitespace before folding, so "10 -20" and
  "10-20" fold alike (spec/07 §7.1).
- Grades are summed with exact decimals; the reviewer error bound is
  computed with integer arithmetic.
- receipts and revocations are keyed by (doc_key, id) in SQL, since one
  revocation may be carried by several packages.

Checking:

- tools/stress.py: seeded randomized property tests over canonical JSON,
  normalization, notation, random correction walks, anchor resolution,
  Merkle roots, spot-check samples, error bounds, fingerprints, mutated
  archives and packages, rights and spot-check chains; CI runs it.
- check.py verifies every count and version the prose states against
  the repository, the zipped fixture and crafted archives, the checklist
  coverage, and nine more broken packages.
- CONTRIBUTING.md gains a release checklist.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tools/oracle/tree.py

@@ -212,5 +212,38 @@ def _check_content(doc, nid):
         raise Refusal("doc.node.attrs", "a section needs a level", nid)
 
 
+def validate_references(doc):
+    """Check the references between nodes: cite, fnmark and xref runs, and the header paths of tables and rows
+    (spec/03 §3.4–3.5, spec/09 §9.2). Raises Refusal."""
+    kinds = {nid: doc.nodes[nid]["kind"] for nid in doc.order}
+    for nid in doc.order:
+        n = doc.nodes[nid]
+        if n["kind"] in RUN_KINDS and not n.get("withheld"):
+            for r in n.get("content") or []:
+                if r["kind"] == "cite":
+                    for ref in r["refs"]:
+                        if kinds.get(ref) != "reference":
+                            raise Refusal("doc.run.cite", "cite names %s, which is not a reference" % ref, nid)
+                if r["kind"] == "fnmark" and r.get("footnote") is not None and kinds.get(r["footnote"]) != "footnote":
+                    raise Refusal("doc.run.fnmark", "fnmark names a node that is not a footnote", nid)
+                if r["kind"] == "xref" and r.get("target") and "#" not in r["target"] and r["target"] not in kinds:
+                    raise Refusal("doc.run.xref", "xref names no node in this document", nid)
+        if n["kind"] == "table":
+            for col in n.get("attrs", {}).get("columns", []):
+                for h in col["header_path"]:
+                    if kinds.get(h) != "cell":
+                        raise Refusal("doc.table.header", "a header path names %s, not a cell" % h, nid)
+        if n["kind"] == "row":
+            for h in n.get("attrs", {}).get("header_path", []):
+                if kinds.get(h) != "cell":
+                    raise Refusal("doc.table.header", "a row header path names %s, not a cell" % h, nid)
+        if n["kind"] == "cell":
+            col = n.get("attrs", {}).get("column")
+            table = next((a for a in reversed(doc.ancestors(nid)) if kinds[a] == "table"), None)
+            columns = {c["id"] for c in doc.nodes[table].get("attrs", {}).get("columns", [])} if table else set()
+            if col is not None and columns and col not in columns:
+                raise Refusal("doc.table.header", "a cell names a column its table does not define", nid)
+
+
 def leaf_kinds():
     return LEAVES