Handles automatic JavaScript hooks integration for PhoenixKit installation.

This module:

• Copies phoenix_kit.js to the parent app's priv/static/assets/vendor/
• Adds a <script> tag to the root layout so hooks are loaded before LiveSocket

The JS file defines window.PhoenixKitHooks which is spread into LiveSocket's hooks object in app.js: hooks: { ...window.PhoenixKitHooks, ...colocatedHooks }

External module hooks

External modules declare prebuilt hook bundles via js_sources/0. The :phoenix_kit_js_sources compiler concatenates those into priv/static/assets/vendor/phoenix_kit_modules.js on every compile and folds their hooks into window.PhoenixKitHooks. This module:

• registers that compiler in the parent app's mix.exs,
• adds a single (stable) <script> tag for the aggregate file after phoenix_kit.js and before app.js,
• seeds an empty aggregate file so the tag doesn't 404 before the first compile.

The tag never changes as modules come and go — only the file's content does — so module JS stays zero-config, exactly like css_sources/0.