/**
 * Convert an ASN.1 DER-encoded P-256 ECDSA signature into the raw `r‖s`
 * (IEEE P1363) fixed-width form the Web Crypto API requires for
 * `crypto.subtle.verify`: 64 bytes, each component big-endian and left-padded
 * with zeros.
 *
 * The passkey path feeds this **attacker-controlled** input, so the parser is
 * strict and bounds-checked end to end: it reads no byte without first proving
 * it is in range, validates every ASN.1 tag and length, rejects long-form
 * lengths (a conformant P-256 signature is always short-form), forbids trailing
 * bytes, and refuses any component wider than the 32-byte field. On any
 * structural problem it throws — callers translate that into a *failed* (not
 * crashed) verification rather than a 500.
 *
 * Leading-zero handling is deliberately lenient: it strips DER sign/padding
 * bytes to recover each component's magnitude, so a non-minimal encoding still
 * maps to the correct (r, s). For well-formed *minimal* DER (e.g. the output of
 * `crypto.subtle.sign`) the result is byte-identical to a naive parser.
 *
 * @param der DER bytes: `0x30 len 0x02 rLen r 0x02 sLen s`.
 * @returns `r‖s`, exactly 64 bytes.
 * @throws {Error} when `der` is not a structurally valid two-INTEGER DER
 *   sequence, or a component exceeds the 32-byte field width.
 */
export declare function derToRawEcdsaSignature(der: Uint8Array): Uint8Array;