search: fuzzy matching via edit distance + 18 tests

editDist as an O(m*n) row-based Levenshtein DP (naive recursion is exponential
and times out under load); fuzzyTerms/fuzzyDocs/fuzzyRankTfIdf expand a term to
indexed terms within a max edit distance. 166/166.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/search/api.sx

@@ -5,7 +5,8 @@
 ;; docFreq, allTerms, tokens, positioned, evalQuery, parseQuery, searchQuery,
 ;; rankTfIdf, rankBm25, topNTfIdf, topNBm25, fedIndex, aclFilter, searchTfIdfAcl,
 ;; topNTfIdfAcl, searchBm25Acl, prefixTerms, prefixDocs, prefixRankTfIdf,
-;; paginate, pageTfIdf, pageBm25, resultCount.
+;; paginate, pageTfIdf, pageBm25, resultCount, editDist, fuzzyTerms, fuzzyDocs,
+;; fuzzyRankTfIdf.
 
 (define
   search/src
@@ -24,4 +25,6 @@
     "\n"
     search/prefix-src
     "\n"
-    search/page-src))
+    search/page-src
+    "\n"
+    search/fuzzy-src))