feat(wasm): parse_lastpass_csv_json bridge

Returns { items: [Item], warnings: [ImportWarning] } as a JSON
string. The items already have fresh IDs + timestamps; the SW
caller encrypts and writes them through the existing
item_encrypt + manifest_encrypt bridges.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

crates/relicario-wasm/src/lib.rs

@@ -432,6 +432,28 @@ pub fn unpack_backup_json(bytes: &[u8], passphrase: &str) -> Result<String, JsEr
     Ok(json.to_string())
 }
 
+// ── LastPass CSV importer bridge ────────────────────────────────────────────
+
+use relicario_core::import_lastpass::parse_lastpass_csv as core_parse_lastpass_csv;
+
+/// Parse a LastPass CSV into `{ items: [Item], warnings: [ImportWarning] }`.
+///
+/// Items are returned as full `Item` JSON objects with freshly-minted IDs
+/// and timestamps already populated. The SW caller is responsible for
+/// encrypting + writing them; this bridge stays pure so the preview UI
+/// can render counts without committing anything.
+#[wasm_bindgen]
+pub fn parse_lastpass_csv_json(csv_bytes: &[u8]) -> Result<String, JsError> {
+    let (items, warnings) = core_parse_lastpass_csv(csv_bytes)
+        .map_err(|e| JsError::new(&e.to_string()))?;
+
+    let json = serde_json::json!({
+        "items": items,
+        "warnings": warnings,
+    });
+    Ok(json.to_string())
+}
+
 #[cfg(test)]
 mod session_tests {
     use super::*;
@@ -474,4 +496,31 @@ mod session_tests {
         let bytes2 = manifest_encrypt(&handle, &serde_json::to_string(&empty).unwrap()).unwrap();
         assert_ne!(bytes, bytes2, "nonces must differ");
     }
+
+    #[test]
+    fn parse_lastpass_csv_json_returns_items_and_warnings() {
+        // Row 1 imports cleanly; row 2 has an empty `name` and is skipped
+        // with a warning.
+        let csv = "url,username,password,totp,extra,name,grouping,fav\n\
+                   https://x,alice,hunter2,,,GitHub,Work,1\n\
+                   https://y,bob,hunter2,,,,,";
+        let json = super::parse_lastpass_csv_json(csv.as_bytes()).unwrap();
+        let v: serde_json::Value = serde_json::from_str(&json).unwrap();
+        assert_eq!(v["items"].as_array().unwrap().len(), 1);
+        assert_eq!(v["warnings"].as_array().unwrap().len(), 1);
+        assert!(v["warnings"][0]["message"].as_str().unwrap().contains("name"));
+        // The item's title round-trips as a plain JSON string.
+        assert_eq!(v["items"][0]["title"].as_str().unwrap(), "GitHub");
+    }
+
+    #[test]
+    fn parse_lastpass_csv_json_propagates_header_errors() {
+        // Test the underlying core function directly since native tests
+        // can't call wasm_bindgen functions.
+        use relicario_core::import_lastpass::parse_lastpass_csv;
+        let bad = "name,user,pass\nA,u,p\n";
+        let err = parse_lastpass_csv(bad.as_bytes());
+        // Should fail with a header validation error.
+        assert!(err.is_err());
+    }
 }