fix(parser): handle raw SeedPGP payloads without prefix

Modifies the frame parsing logic to accommodate Base45-encoded SeedPGP payloads that are missing the 'SEEDPGP1:' prefix and CRC. This scenario occurs with certain QR code generators, such as some modes on Krux devices.

- `frameParse` now detects when the prefix is missing and treats the entire input as a raw Base45 payload.
- A `rawPayload` flag is added to the `ParsedSeedPgpFrame` type to signal this case.
- `frameDecodeToPgpBytes` now bypasses the CRC check when this flag is true, allowing the decryption to proceed.
- This resolves a bug where valid encrypted payloads were being rejected due to a missing frame structure.

src/lib/seedpgp.ts

@@ -53,28 +53,37 @@ export function frameEncode(pgpBinary: Uint8Array): string {
 
 export function frameParse(text: string): ParsedSeedPgpFrame {
     const s = text.trim().replace(/^["']|["']$/g, "").replace(/[\n\r\t]/g, "");
-    if (!s.startsWith("SEEDPGP1:")) throw new Error("Missing SEEDPGP1: prefix");
+    if (s.startsWith("SEEDPGP1:")) {
+        const parts = s.split(":");
+        if (parts.length < 4) {
+            throw new Error("Invalid frame format (need at least 4 colon-separated parts)");
+        }
+        const prefix = parts[0];
+        const frame = parts[1];
+        const crc16 = parts[2].toUpperCase();
+        const b45 = parts.slice(3).join(":");
 
-    const parts = s.split(":");
-    if (parts.length < 4) {
-        throw new Error("Invalid frame format (need at least 4 colon-separated parts)");
+        if (prefix !== "SEEDPGP1") throw new Error("Invalid prefix");
+        if (frame !== "0") throw new Error("Multipart frames not supported in this prototype");
+        if (!/^[0-9A-F]{4}$/.test(crc16)) throw new Error("Invalid CRC16 format (must be 4 hex chars)");
+
+        return { kind: "single", crc16, b45 };
+    } else {
+        // It's not a full frame. Assume the ENTIRE string is the base45 payload.
+        // We will have to skip the CRC check.
+        return { kind: "single", crc16: "0000", b45: s, rawPayload: true };
     }
-
-    const prefix = parts[0];
-    const frame = parts[1];
-    const crc16 = parts[2].toUpperCase();
-    const b45 = parts.slice(3).join(":");
-
-    if (prefix !== "SEEDPGP1") throw new Error("Invalid prefix");
-    if (frame !== "0") throw new Error("Multipart frames not supported in this prototype");
-    if (!/^[0-9A-F]{4}$/.test(crc16)) throw new Error("Invalid CRC16 format (must be 4 hex chars)");
-
-    return { kind: "single", crc16, b45 };
 }
 
 export function frameDecodeToPgpBytes(frameText: string): Uint8Array {
     const f = frameParse(frameText);
     const pgp = base45Decode(f.b45);
+
+    // If it's a raw payload, we cannot and do not verify the CRC.
+    if (f.rawPayload) {
+        return pgp;
+    }
+
     const crc = crc16CcittFalse(pgp);
     if (crc !== f.crc16) {
         throw new Error(`CRC16 mismatch! Expected: ${f.crc16}, Got: ${crc}. QR scan may be corrupted.`);

src/lib/types.ts

@@ -11,6 +11,7 @@ export type ParsedSeedPgpFrame = {
     kind: "single";
     crc16: string;
     b45: string;
+    rawPayload?: boolean;
 };
 
 // Krux KEF types