feat: add release notes banner

[Faraz32123]

Ticket: TNL2-370
In this PR,

• add release notes banner including link to release notes page

Screen.Recording.2025-10-06.at.6.31.23.PM.mov

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[Copilot]

Pull Request Overview

This PR adds a release notes banner feature to the course authoring interface. The banner promotes the new release notes functionality with a dismissible notification that includes a link to the dedicated release notes page.

• Adds a new release notes page component and routing
• Implements a dismissible page banner with internationalized messaging
• Adds environment variable configuration for enabling/disabling the banner

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/release-notes/messages.js	Defines i18n messages for banner text and link text
src/release-notes/ReleaseNotes.scss	Styles for the page banner with custom colors and typography
src/release-notes/ReleaseNotes.jsx	Basic release notes page component
src/index.scss	Imports the new SCSS file
src/index.jsx	Adds environment variable configuration for banner control
src/course-outline/CourseOutline.tsx	Integrates the banner into the course outline page
src/CourseAuthoringRoutes.jsx	Adds routing for the release notes page

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[Copilot]

Pull Request Overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

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