Android sharing sends the opened device token, not the sealed one

Android has stored its device token sealed ("sealed:…") since 8592b83, and
core's sharing calls read the token from the store themselves. The ffi opened
it in credentials() and then threw the result away, so every Share-sheet
request went out as `Bearer sealed:…` and the server refused it.

The sharing functions now take the server address and token from the caller.
The ffi passes what credentials() opened; the desktop, which stores its token
plain, reads it through sharing::stored_link. A new ffi test serves one request
on a loopback port and checks the bearer token that arrives (#5381).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

desktop/src-tauri/src/commands/sync.rs

@@ -194,12 +194,14 @@ pub fn sync_has_pending(db: State<'_, Db>) -> Result<bool, String> {
 
 #[tauri::command]
 pub async fn shares_directory(db: State<'_, Db>) -> Result<Directory, String> {
-    sharing::directory(&db).await
+    let (url, token) = sharing::stored_link(&db)?;
+    sharing::directory(&url, &token).await
 }
 
 #[tauri::command]
 pub async fn shares_list(note_id: String, db: State<'_, Db>) -> Result<Vec<NoteShare>, String> {
-    sharing::list(&db, &note_id).await
+    let (url, token) = sharing::stored_link(&db)?;
+    sharing::list(&db, &url, &token, &note_id).await
 }
 
 /// Share with a person (`user_id`) or a group (`group_id`, #5177): exactly one.
@@ -216,7 +218,8 @@ pub async fn shares_share(
         (None, Some(id)) => ShareTarget::Group(id),
         _ => return Err("Choose someone or a group to share with.".to_string()),
     };
-    sharing::share(&db, &note_id, &target, &permission).await
+    let (url, token) = sharing::stored_link(&db)?;
+    sharing::share(&db, &url, &token, &note_id, &target, &permission).await
 }
 
 #[tauri::command]
@@ -225,5 +228,6 @@ pub async fn shares_unshare(
     share_id: String,
     db: State<'_, Db>,
 ) -> Result<Vec<NoteShare>, String> {
-    sharing::unshare(&db, &note_id, &share_id).await
+    let (url, token) = sharing::stored_link(&db)?;
+    sharing::unshare(&db, &url, &token, &note_id, &share_id).await
 }