refactor(list-messages): switch from page-based to cursor-based pagination

- Changed `list-messages` API from page/page_size to cursor/next_page_token
- Aligns pagination approach with Gmail API for easier integration
- Frontend updates to handle cursor-based navigation

src/modules/cache/vendor/gmail/sync/client.rs

@@ -202,9 +202,9 @@ impl GmailClient {
         account_id: u64,
         use_proxy: Option<u64>,
         label_id: &str,
-        page_token: Option<String>,
+        page_token: Option<&str>,
         after: Option<&str>,
-        max_results: u32,
+        max_results: u64,
     ) -> RustMailerResult<MessageList> {
         let mut url = format!(
             "https://gmail.googleapis.com/gmail/v1/users/me/messages?labelIds={}&maxResults={}",

src/modules/cache/vendor/gmail/sync/flow.rs

@@ -43,9 +43,9 @@ pub async fn fetch_and_save_since_date(
             account_id,
             use_proxy,
             &label.label_id,
-            page_token,
+            page_token.as_deref(),
             Some(date),
-            ENVELOPE_BATCH_SIZE,
+            ENVELOPE_BATCH_SIZE as u64,
         )
         .await?;
         // The total number of messages can only be retrieved via an API query
@@ -156,9 +156,9 @@ pub async fn fetch_and_save_full_label(
             account_id,
             use_proxy,
             &label.label_id,
-            page_token,
+            page_token.as_deref(),
             None,
-            ENVELOPE_BATCH_SIZE,
+            ENVELOPE_BATCH_SIZE as u64,
         )
         .await?;
         // Update page_token returned by Gmail API