Fix backend issues in desktop app (#4995)

# Description of Changes
Fixes two distinct but related issues in the backend of the desktop app:
- Correctly shows tools as unavaialable when the backend doesn't have
the dependencies or has disabled them etc. (same as web version - this
primarily didn't work on desktop because the app spawns before the
backend is running)
- Fixes infinite re-rendering issues caused by the app polling whether
the backend is healthy or not

frontend/src-tauri/src/commands/health.rs

@@ -1,16 +0,0 @@
-use reqwest;
-
-#[tauri::command]
-pub async fn check_backend_health(port: u16) -> Result<bool, String> {
-    let url = format!("http://localhost:{}/api/v1/info/status", port);
-
-    match reqwest::Client::new()
-        .get(&url)
-        .timeout(std::time::Duration::from_secs(5))
-        .send()
-        .await
-    {
-        Ok(response) => Ok(response.status().is_success()),
-        Err(_) => Ok(false), // Return false instead of error for connection failures
-    }
-}

frontend/src-tauri/src/commands/mod.rs

@@ -3,7 +3,6 @@ pub mod files;
 pub mod connection;
 pub mod auth;
 pub mod default_app;
-pub mod health;
 
 pub use backend::{cleanup_backend, get_backend_port, start_backend};
 pub use files::{add_opened_file, clear_opened_files, get_opened_files};
@@ -24,4 +23,3 @@ pub use auth::{
     start_oauth_login,
 };
 pub use default_app::{is_default_pdf_handler, set_as_default_pdf_handler};
-pub use health::check_backend_health;

frontend/src-tauri/src/lib.rs

@@ -6,7 +6,6 @@ mod state;
 
 use commands::{
     add_opened_file,
-    check_backend_health,
     cleanup_backend,
     clear_auth_token,
     clear_opened_files,
@@ -94,7 +93,6 @@ pub fn run() {
       set_as_default_pdf_handler,
       is_first_launch,
       reset_setup_completion,
-      check_backend_health,
       login,
       save_auth_token,
       get_auth_token,