WP Bulk Image Alt Editor

I want a lightweight WordPress plugin that lives inside the Media Library and lets me overwrite ALT-text on many images at once. The workflow I have in mind is simple:

• A single input field where I type the custom text that will become the new ALT for selected images.
• A file-list style picker (checkboxes or similar) so I can choose exactly which images receive that text; it should not force the change on the entire library.
• When I press “Apply”, the plugin must replace the existing ALT value entirely—no prefixes, no suffixes, just the text I entered.

Please keep the interface native to WordPress, avoid bulky frameworks, and make sure the code is fully GPL-compatible. The finished deliverable is a .zip I can upload through the normal “Add Plugin” screen plus a short read-me covering installation, usage, and uninstall steps. Compatibility with current stable WordPress and the standard Media Library is essential; no Gutenberg dependencies are required.