feat: add tauriReady function to core

[alexmoon]

Closes #12348.

Adds a tauriReady() function to @tauri-apps/api/core which returns a promise that resolves when all of Tauri's initialization scripts have finished.

This allows users to work around an issue observed on Windows where the webview is running the page's scripts before the initialization scripts have finished running, leading to errors when attempting to access Tauri APIs before they have been initialized.

I have observed cases where my page's scripts appear to be run between initialization scripts (i.e. some initialization scripts have run but others have not), so this adds a new initialization script to the end of the sequence to set the ready flag and dispatch the event to ensure that all other initialization scripts have finished running before the ready flag is set.

[github-actions]

Package Changes Through 29afa36

There are 7 changes which include tauri-cli with minor, tauri-runtime with minor, tauri-runtime-wry with minor, tauri-utils with minor, tauri with minor, @tauri-apps/api with minor, @tauri-apps/cli with minor

Planned Package Versions

The following package releases are the planned based on the context of changes in this pull request.

package	current	next
@tauri-apps/api	2.2.0	2.3.0
tauri-utils	2.1.1	2.2.0
tauri-bundler	2.2.3	2.2.4
tauri-runtime	2.3.0	2.4.0
tauri-runtime-wry	2.3.0	2.4.0
tauri-codegen	2.0.4	2.0.5
tauri-macros	2.0.4	2.0.5
tauri-plugin	2.0.4	2.0.5
tauri-build	2.0.5	2.0.6
tauri	2.2.5	2.3.0
@tauri-apps/cli	2.2.7	2.3.0
tauri-cli	2.2.7	2.3.0

Add another change file through the GitHub UI by following this link.

---

Read about change files or the docs at github.com/jbolda/covector