cli: --totp-qr <path> flag on add login + edit (rqrr decode)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/relicario-cli/src/helpers.rs

@@ -115,6 +115,34 @@ pub fn write_groups_cache(
     std::fs::write(path, body)
 }
 
+/// Decode a QR image at `path`. Returns the otpauth secret (base32) if the
+/// QR decodes to an `otpauth://...` URI with a `secret` query param.
+pub fn decode_totp_qr(path: &std::path::Path) -> anyhow::Result<String> {
+    let img = image::open(path)
+        .map_err(|e| anyhow::anyhow!("failed to read image: {e}"))?
+        .to_luma8();
+    let mut prepared = rqrr::PreparedImage::prepare(img);
+    let grids = prepared.detect_grids();
+    let grid = grids
+        .into_iter()
+        .next()
+        .ok_or_else(|| anyhow::anyhow!("no QR code found in image"))?;
+    let (_meta, content) = grid
+        .decode()
+        .map_err(|e| anyhow::anyhow!("QR decode failed: {e}"))?;
+    if !content.starts_with("otpauth://") {
+        return Err(anyhow::anyhow!("not a TOTP URI (expected otpauth://...)"));
+    }
+    let parsed =
+        url::Url::parse(&content).map_err(|e| anyhow::anyhow!("invalid otpauth URI: {e}"))?;
+    let secret = parsed
+        .query_pairs()
+        .find(|(k, _)| k == "secret")
+        .map(|(_, v)| v.to_string())
+        .ok_or_else(|| anyhow::anyhow!("otpauth URI missing `secret` parameter"))?;
+    Ok(secret)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;