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/history.ts

@@ -1,49 +1,100 @@
 /** Decode the two Git path tokens in a `diff --git` header. */
-function token(source:string,offset:number):{value:string;next:number}|undefined{
-  if(source[offset]!=='"'){
-    const end=source.indexOf(' ',offset),next=end<0?source.length:end;
-    if(next===offset)return;
-    return{value:source.slice(offset,next),next};
+function token(source: string, offset: number): { value: string; next: number } | undefined {
+  if (source[offset] !== '"') {
+    const end = source.indexOf(' ', offset),
+      next = end < 0 ? source.length : end;
+    if (next === offset) return;
+    return { value: source.slice(offset, next), next };
   }
-  const bytes:number[]=[];let at=offset+1;
-  const append=(value:string)=>bytes.push(...new TextEncoder().encode(value));
-  while(at<source.length){
-    const value=source[at++];
-    if(value==='"')return{value:new TextDecoder('utf-8',{fatal:true}).decode(Uint8Array.from(bytes)),next:at};
-    if(value!=='\\'){append(value);continue;}
-    if(at>=source.length)return;
-    const escaped=source[at++],mapped:{[key:string]:string}={a:'\x07',b:'\b',f:'\f',n:'\n',r:'\r',t:'\t',v:'\v','\\':'\\','"':'"'};
-    if(mapped[escaped]!==undefined){append(mapped[escaped]);continue;}
-    if(/[0-7]/.test(escaped)&&/^[0-7]{2}/.test(source.slice(at,at+2))){bytes.push(Number.parseInt(escaped+source.slice(at,at+2),8));at+=2;continue;}
+  const bytes: number[] = [];
+  let at = offset + 1;
+  const append = (value: string) => bytes.push(...new TextEncoder().encode(value));
+  while (at < source.length) {
+    const value = source[at++];
+    if (value === '"')
+      return { value: new TextDecoder('utf-8', { fatal: true }).decode(Uint8Array.from(bytes)), next: at };
+    if (value !== '\\') {
+      append(value);
+      continue;
+    }
+    if (at >= source.length) return;
+    const escaped = source[at++],
+      mapped: { [key: string]: string } = {
+        a: '\x07',
+        b: '\b',
+        f: '\f',
+        n: '\n',
+        r: '\r',
+        t: '\t',
+        v: '\v',
+        '\\': '\\',
+        '"': '"',
+      };
+    if (mapped[escaped] !== undefined) {
+      append(mapped[escaped]);
+      continue;
+    }
+    if (/[0-7]/.test(escaped) && /^[0-7]{2}/.test(source.slice(at, at + 2))) {
+      bytes.push(Number.parseInt(escaped + source.slice(at, at + 2), 8));
+      at += 2;
+      continue;
+    }
     return;
   }
 }
 
-export function gitDiffHeaderPaths(line:string):[string,string]|undefined{
-  const prefix='diff --git ';if(!line.startsWith(prefix))return;
-  try{
-    const left=token(line,prefix.length);if(!left||line[left.next]!==' ')return;
-    const right=token(line,left.next+1);if(!right||right.next!==line.length)return;
-    return[left.value,right.value];
-  }catch{return;}
+export function gitDiffHeaderPaths(line: string): [string, string] | undefined {
+  const prefix = 'diff --git ';
+  if (!line.startsWith(prefix)) return;
+  try {
+    const left = token(line, prefix.length);
+    if (!left || line[left.next] !== ' ') return;
+    const right = token(line, left.next + 1);
+    if (!right || right.next !== line.length) return;
+    return [left.value, right.value];
+  } catch {
+    return;
+  }
 }
 
 /** Return only exact path hunks, keeping one commit preamble per matching commit. */
-export function historyForPath(raw:string,path:string):string|undefined{
-  const expected=new Set([`a/${path}`,`b/${path}`]),output:string[]=[],lines=raw.split('\n');
-  let preamble:string[]=[],section:string[]|undefined,include=false,preambleEmitted=false;
-  const flush=()=>{
-    if(section&&include){if(!preambleEmitted){output.push(...preamble);preambleEmitted=true;}output.push(...section);}
-    section=undefined;include=false;
-  };
-  for(const line of lines){
-    if(line.startsWith('commit ')){flush();preamble=[line];preambleEmitted=false;continue;}
-    if(line.startsWith('diff --git ')){
-      flush();section=[line];const paths=gitDiffHeaderPaths(line);include=Boolean(paths&&(expected.has(paths[0])||expected.has(paths[1])));continue;
+export function historyForPath(raw: string, path: string): string | undefined {
+  const expected = new Set([`a/${path}`, `b/${path}`]),
+    output: string[] = [],
+    lines = raw.split('\n');
+  let preamble: string[] = [],
+    section: string[] | undefined,
+    include = false,
+    preambleEmitted = false;
+  const flush = () => {
+    if (section && include) {
+      if (!preambleEmitted) {
+        output.push(...preamble);
+        preambleEmitted = true;
+      }
+      output.push(...section);
     }
-    if(section)section.push(line);else preamble.push(line);
+    section = undefined;
+    include = false;
+  };
+  for (const line of lines) {
+    if (line.startsWith('commit ')) {
+      flush();
+      preamble = [line];
+      preambleEmitted = false;
+      continue;
+    }
+    if (line.startsWith('diff --git ')) {
+      flush();
+      section = [line];
+      const paths = gitDiffHeaderPaths(line);
+      include = Boolean(paths && (expected.has(paths[0]) || expected.has(paths[1])));
+      continue;
+    }
+    if (section) section.push(line);
+    else preamble.push(line);
   }
   flush();
-  while(output.at(-1)==='')output.pop();
-  return output.length?output.join('\n'):undefined;
+  while (output.at(-1) === '') output.pop();
+  return output.length ? output.join('\n') : undefined;
 }