feat(authors): allow correcting metadata matches

Let users edit author facts, choose and pin a provider record, and keep later refreshes tied to that record. Preserve compatibility for older clients through additive API fields and a discoverable server feature.

Keep server typechecking deterministic by breaking circular Drizzle inference and correcting the nullability mismatches it previously hid.

Closes #1464

server/test/e2e/authorization-matrix/route-inventory/manifest.json

@@ -1,10 +1,10 @@
 {
-  "totalRoutes": 665,
+  "totalRoutes": 667,
   "byPermission": {
     "(none)": 287,
     "Permission.ManageMetadataConfig": 41,
     "Permission.EmailSend": 34,
-    "Permission.LibraryEditMetadata": 35,
+    "Permission.LibraryEditMetadata": 37,
     "Permission.BookDockAccess": 17,
     "Permission.ManageAppSettings": 62,
     "Permission.ManageLibraries": 24,

server/test/e2e/authorization-matrix/route-inventory/routes-02.json

@@ -47,6 +47,30 @@
     "allowDefault": false,
     "useGuards": []
   },
+  {
+    "file": "server/src/modules/authors/authors.controller.ts",
+    "className": "AuthorsController",
+    "methodName": "pinMetadataMatch",
+    "httpMethod": "PUT",
+    "path": "/authors/:id/metadata-match",
+    "permissions": ["Permission.LibraryEditMetadata"],
+    "libraryAccess": [],
+    "isPublic": false,
+    "allowDefault": false,
+    "useGuards": []
+  },
+  {
+    "file": "server/src/modules/authors/authors.controller.ts",
+    "className": "AuthorsController",
+    "methodName": "unpinMetadataMatch",
+    "httpMethod": "DELETE",
+    "path": "/authors/:id/metadata-match",
+    "permissions": ["Permission.LibraryEditMetadata"],
+    "libraryAccess": [],
+    "isPublic": false,
+    "allowDefault": false,
+    "useGuards": []
+  },
   {
     "file": "server/src/modules/authors/authors.controller.ts",
     "className": "AuthorsController",