feat: add Builder::append_invoke_initialization_script (#10295)

* Allow to append a custom initialization script

* docs: add doc for `Builder::append_invoke_initialization_script`

* Update core/tauri/src/app.rs

* Update core/tauri/src/app.rs

* add change file

* fix signature

* fix doc test

* doc fmt

---------

Co-authored-by: Lucas Fernandes Nogueira <lucas@tauri.app>

Author: liesauer

.changes/append_invoke_initialization_script.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch:enhance
+---
+
+Added `Builder::append_invoke_initialization_script`.

core/tauri/src/app.rs

@@ -1328,6 +1328,53 @@ impl<R: Runtime> Builder<R> {
     self
   }
 
+  /// Append a custom initialization script.
+  ///
+  /// Allow to append custom initialization script instend of replacing entire invoke system.
+  ///
+  /// # Examples
+  ///
+  /// ```
+  /// let custom_script = r#"
+  /// // A custom call system bridge build on top of tauri invoke system.
+  /// async function invoke(cmd, args = {}) {
+  ///   if (!args) args = {};
+  ///
+  ///   let prefix = "";
+  ///
+  ///   if (args?.__module) {
+  ///     prefix = `plugin:hybridcall.${args.__module}|`;
+  ///   }
+  ///
+  ///   const command = `${prefix}tauri_${cmd}`;
+  ///
+  ///   const invoke = window.__TAURI_INTERNALS__.invoke;
+  ///
+  ///   return invoke(command, args).then(result => {
+  ///     if (window.build.debug) {
+  ///       console.log(`call: ${command}`);
+  ///       console.log(`args: ${JSON.stringify(args)}`);
+  ///       console.log(`return: ${JSON.stringify(result)}`);
+  ///     }
+  ///
+  ///     return result;
+  ///   });
+  /// }
+  /// "#;
+  ///
+  /// tauri::Builder::default()
+  ///   .append_invoke_initialization_script(custom_script);
+  /// ```
+  pub fn append_invoke_initialization_script(
+    mut self,
+    initialization_script: impl AsRef<str>,
+  ) -> Self {
+    self
+      .invoke_initialization_script
+      .push_str(initialization_script.as_ref());
+    self
+  }
+
   /// Defines the setup hook.
   ///
   /// # Examples