Fix platform-specific standalone build warnings

docs/specs/standalone.md

@@ -960,6 +960,8 @@ written.
   `session_temp_suffix_matches_what_the_writer_leaves`.
   Transcript migration follows `docs/specs/transport.md` → "Retiring the transcripts already on disk".
 
+Source of truth: `write_file_with_permissions` in `standalone/src-tauri/src/lib.rs`.
+
 **Must use `<app_data_dir>/dev` as the debug state root and `<app_data_dir>` for
 release builds** (rationale). `app_data_dir()` follows the Tauri identifier;
 `pnpm dev:standalone` already supplies a distinct per-worktree identifier
@@ -1221,7 +1223,7 @@ with only the exit changed.
   then `tauri::process::restart`, which on macOS re-reads `Info.plist`, so a
   bundle replaced in place starts as the new version. **Never
   `AppHandle::request_restart`** (rationale).
-- **A terminate the OS re-sends after approval clears the intent**, so logout
+- **Must clear the restart intent when macOS re-sends an OS terminate after approval**, so logout
   never relaunches.
 - **`quit_restart` refuses a debug build and an executable
   `tauri::process::current_binary` cannot resolve**, where `restart` would exit

standalone/src-tauri/src/lib.rs

@@ -1839,7 +1839,7 @@ fn write_file_with_permissions(
     contents: &str,
     restrict: impl Fn(&Path, u32) -> Result<(), String>,
 ) -> Result<(), String> {
-    let dir = ensure_parent_with(path, &restrict)?;
+    let _dir = ensure_parent_with(path, &restrict)?;
     let tmp = temp_write_path(path);
     // Atomic replace: write a sibling temp file, fsync it, then rename over the
     // target so a crash mid-write can never truncate the previous good copy.
@@ -1869,7 +1869,7 @@ fn write_file_with_permissions(
     // equivalent dir-fsync concept, so this is unix-only.
     #[cfg(unix)]
     {
-        if let Ok(d) = std::fs::File::open(dir) {
+        if let Ok(d) = std::fs::File::open(_dir) {
             let _ = d.sync_all();
         }
     }

standalone/src-tauri/src/quit_state.rs

@@ -234,6 +234,7 @@ impl QuitMachine {
 
     /// The OS is ending the app itself (Dock Quit, logout), which never
     /// relaunches.
+    #[cfg(any(target_os = "macos", test))]
     pub fn forget_restart(&mut self) {
         self.intent = QuitIntent::default();
     }