Polyglot Media Camouflage

+-------------------------------------------------------------------------+
| Authentic Media Header & Bitstream (Bytes 0 .. K)                        |
| e.g. Valid JPEG (FF D8 ... FF D9) or PNG (89 50 4E 47 ... IEND)        |
+-------------------------------------------------------------------------+
| ZERO-BYTE TERMINATION BOUNDARY (Offset K)                               |
+-------------------------------------------------------------------------+
| Authentic ZV3 Container Header (Bytes K .. K + 57)                      |
| [ 'ZV3\0' (4B) | VERSION: 0x03 | FLAGS | CHUNK_SIZE | SALT | IV | OFFSET ]|
+-------------------------------------------------------------------------+
| STREAM AEAD 4 MB Ciphertext Chunks + Tail Manifest Trailer              |
+-------------------------------------------------------------------------+

// js/stream-unpacker.js: Zero-allocation sliding-window detector
function findPolyglotVaultOffset(buffer) {
    const bytes = new Uint8Array(buffer);
    // 1. Fast check: is this a standard standalone vault?
    if (bytes[0] === 0x5A && bytes[1] === 0x56 && bytes[2] === 0x33 && bytes[3] === 0x00) {
        return 0; // Standard offset
    }

    // 2. Scan for 'ZV3\0' magic signature within first 64 MB
    const maxScan = Math.min(bytes.length - 57, 64 * 1024 * 1024);
    for (let i = 0; i < maxScan; i++) {
        if (bytes[i] === 0x5A && bytes[i+1] === 0x56 && bytes[i+2] === 0x33 && bytes[i+3] === 0x00) {
            // Verify version byte at offset + 4
            if (bytes[i+4] === 0x03) {
                return i; // Found authentic polyglot container offset!
            }
        }
    }
    return -1; // No vault signature detected
}