fix(microlearning): responsive cards, consistent navigation and clearer activity step

[noor-lpi]

Summary

Layout

• Step 1 flip cards grow to fit their text, so nothing overflows on small screens. All cards are the same height, and there's 1 column on mobile.
• The steps column is wider (full width, max 960px). Contribution titles are bold.

Navigation

• The same footer on every screen after Welcome: Previous on the left, main button on the right, and "Skip" / hints underneath.
• Previous now also goes from step 1 back to the self-assessment, and from the "after" self-assessment back to step 4.
• The header's "Restart" is now "Change discipline", with a confirmation.
• Browser back/forward follow the app's navigation (the screen is written into the URL; ?lang= is kept).
• Progress is kept when going back: flipped cards, the chosen activity, reflection answers and self-assessment answers.

Self-assessment

• Answers are held in shared state instead of being thrown away when the screen changes.
• The "before" answers are locked once the steps start, to keep the research baseline clean.

Steps requiring an action

• Next is disabled until the action is done, with a hint ("Flip all the cards…" / "Choose an activity…").
• Cards can be flipped back. Activities can be de-selected.

Activity → reflection → end page

• Step 3 has a clear instruction.
• The chosen activity appears in step 4 with a "Change" link, and the last reflection question's example text names it.
• The end page shows the chosen activity and the UVED resource.

Fixes

• The chosen activity and the "Well done!" banner now update when the language is switched.
• Rating buttons and activity cards now work with the keyboard.
• Wording: the contributions are presented as key examples, not "everything". All text changes are in EN and FR.

Note: answers are still only held in memory. They aren't saved to the database, and a page refresh starts over.

🤖 Generated with Claude Code

[sandragjacinto]

nice ! j'aime beaucoup les changements. Pour les flipcards, une fois retournées elle ne devraient pas pouvoir être retournée de nouveau.

[noor-lpi]

merci pour ton retour @sandragjacinto, j'ai fait la modif demandée pour les flipcards.