검증 후 복원하는 합성 자료 모듈

// Fixed-path synthetic bundle; checks integrity, not author identity. Never writes files or production data.
const exact=(v,k)=>v&&typeof v==='object'&&!Array.isArray(v)&&Object.keys(v).sort().join(',')===k;
function validRecords(rows){
 return Array.isArray(rows)&&rows.length<=1000&&rows.every(r=>exact(r,'id,quantity')&&typeof r.id==='string'&&/^S\d{2}$/.test(r.id)&&Number.isSafeInteger(r.quantity)&&r.quantity>=1&&r.quantity<=99)&&new Set(rows.map(r=>r.id)).size===rows.length;
}
async function digest(text){
 if(!globalThis.crypto?.subtle)throw new Error('SHA-256 unavailable');
 const data=await globalThis.crypto.subtle.digest('SHA-256',new TextEncoder().encode(text));
 return Array.from(new Uint8Array(data),n=>n.toString(16).padStart(2,'0')).join('');
}
export async function makeSyntheticBundle(rows){
 if(!validRecords(rows))throw new TypeError('Invalid synthetic records');
 const payload=JSON.stringify(rows),bytes=new TextEncoder().encode(payload).length;
 return JSON.stringify({format:'synthetic-restore-v1',synthetic:true,entry:{path:'records.json',bytes,sha256:await digest(payload)},payload});
}
export async function inspectSyntheticBundle(text){
 if(typeof text!=='string'||text.length>80000)throw new TypeError('Bundle too large or invalid');
 const b=JSON.parse(text);
 if(!exact(b,'entry,format,payload,synthetic')||b.format!=='synthetic-restore-v1'||b.synthetic!==true||!exact(b.entry,'bytes,path,sha256')||b.entry.path!=='records.json'||!Number.isSafeInteger(b.entry.bytes)||b.entry.bytes<0||typeof b.entry.sha256!=='string'||! /^[a-f0-9]{64}$/.test(b.entry.sha256)||typeof b.payload!=='string'||b.payload.length>60000)throw new TypeError('Unsupported synthetic bundle');
 if(new TextEncoder().encode(b.payload).length!==b.entry.bytes||await digest(b.payload)!==b.entry.sha256)throw new Error('Integrity mismatch');
 const rows=JSON.parse(b.payload);if(!validRecords(rows))throw new TypeError('Unsupported synthetic records');
 return {format:b.format,rows:rows.map(r=>({...r})),recordCount:rows.length,sha256:b.entry.sha256};
}
export async function rehearseSyntheticRestore(text,currentRows){
 if(!validRecords(currentRows))throw new TypeError('Invalid target example');
 const checked=await inspectSyntheticBundle(text),oldIds=new Set(currentRows.map(r=>r.id)),newIds=new Set(checked.rows.map(r=>r.id));
 return {candidate:checked.rows,preview:{before:currentRows.length,after:checked.rows.length,added:checked.rows.filter(r=>!oldIds.has(r.id)).length,removed:currentRows.filter(r=>!newIds.has(r.id)).length,changed:checked.rows.filter(r=>currentRows.some(old=>old.id===r.id&&old.quantity!==r.quantity)).length},integrityVerified:true,applied:false};
}