feat: comment categories; emend, relink and resolve corrections

scienting-layer/1: an optional, fixed category on comment, caveat and
question bodies (comment, context, critique, question, correction,
feedback, resource).

Corrections: emend fixes the authors' own slip and keeps what was printed
(a run's printed), never lowering fidelity or a witness match; relink sets
or removes what a citation names; resolve sets a reference's resolution.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017R7sgDNvUGWY2zFPCq2JH6

spec/10-references.md

@@ -9,7 +9,11 @@ Each reference is a `reference` node holding its printed runs, exactly as printe
 | `{type: "document", doc}` | It names a document in the same store, by key. |
 | `{type: "none"}` | Nothing yet. |
 
+A reference without a record has the resolution `none`.
+A `resolve` correction sets a reference's resolution, and its record keeps the one before ([11.7](11-corrections.md#117-citations-and-references)).
+
 Every `cite` run links a sentence to one or more references.
+A `relink` correction changes the references a run names, makes a text run a cite run, or makes a cite run text again, without changing its text ([11.7](11-corrections.md#117-citations-and-references)).
 The citation graph is therefore sentence-level: for any reference, the format gives every sentence that cites it, which is the citation's context.
 The database derives a `citations` table from the runs ([13](13-database.md)).
 An article's references and its Supporting Information's are separate documents' references and never mix.