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

schemas/correction.schema.json

@@ -3,6 +3,18 @@
   "$id": "https://paperspec.scient.ing/schemas/correction.schema.json",
   "title": "Correction",
   "description": "scienting-correction/1: a line of corrections.jsonl, or a proposal; spec/11-corrections.md.",
+  "$defs": {
+    "emendKind": {
+      "enum": [
+        "typo",
+        "spelling",
+        "grammar",
+        "punctuation",
+        "wording",
+        "other"
+      ]
+    }
+  },
   "type": "object",
   "properties": {
     "format": {
@@ -25,7 +37,10 @@
         "move",
         "reclassify",
         "relabel",
-        "set"
+        "set",
+        "emend",
+        "relink",
+        "resolve"
       ]
     },
     "target": {
@@ -71,7 +86,38 @@
       "type": "string"
     },
     "kind": {
-      "$ref": "common.schema.json#/$defs/nodeKind"
+      "description": "A reclassify's new node kind, or what an emend corrects.",
+      "anyOf": [
+        {
+          "$ref": "common.schema.json#/$defs/nodeKind"
+        },
+        {
+          "$ref": "#/$defs/emendKind"
+        }
+      ]
+    },
+    "note": {
+      "type": "string",
+      "minLength": 1
+    },
+    "refs": {
+      "description": "A relink's references: reference node IDs, or null to unlink.",
+      "anyOf": [
+        {
+          "type": "array",
+          "items": {
+            "$ref": "common.schema.json#/$defs/nodeId"
+          },
+          "minItems": 1,
+          "uniqueItems": true
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "resolution": {
+      "$ref": "reference.schema.json#/properties/resolution"
     },
     "label": {
       "anyOf": [
@@ -287,12 +333,74 @@
         }
       },
       "then": {
+        "properties": {
+          "kind": {
+            "$ref": "common.schema.json#/$defs/nodeKind"
+          }
+        },
         "required": [
           "target",
           "kind"
         ]
       }
     },
+    {
+      "if": {
+        "properties": {
+          "op": {
+            "const": "emend"
+          }
+        }
+      },
+      "then": {
+        "properties": {
+          "replace": {
+            "type": "string",
+            "minLength": 1
+          },
+          "kind": {
+            "$ref": "#/$defs/emendKind"
+          }
+        },
+        "required": [
+          "target",
+          "find",
+          "replace",
+          "kind"
+        ]
+      }
+    },
+    {
+      "if": {
+        "properties": {
+          "op": {
+            "const": "relink"
+          }
+        }
+      },
+      "then": {
+        "required": [
+          "target",
+          "run",
+          "refs"
+        ]
+      }
+    },
+    {
+      "if": {
+        "properties": {
+          "op": {
+            "const": "resolve"
+          }
+        }
+      },
+      "then": {
+        "required": [
+          "target",
+          "resolution"
+        ]
+      }
+    },
     {
       "if": {
         "properties": {