style(cso): format lib/cso TypeScript with pinned Prettier

Mechanical reformat only. Minified transpile output is byte-identical for
21 of 22 files; witness.ts differs only in three regex flag orders
(/mi -> /im), which JavaScript canonicalizes. Source-text assertions over
lib/cso now compare whitespace-insensitively with the same tokens.

lib/cso/.prettierrc.json

@@ -0,0 +1,6 @@
+{
+  "printWidth": 110,
+  "singleQuote": true,
+  "trailingComma": "all",
+  "semi": true
+}