FE: Endorsement (upvote)

[MarcHabers]

As a citizen, I want to endorse an existing issue report and see the endorsement count update, so that the community can clearly see which issues matter most.

• Each issue card on the feed includes an Endorse action and shows the current endorsement count.
• Clicking Endorse triggers a backend request to endorse that issue
• After endorsing, the count updates in the UI without a full page reload.
• If the request fails, the UI shown an error massage and the count stays the same.
• Clicking the Endorse button again removes the previously submitted endorsement (toggle behavior), and the endorsement count updates accordingly in the UI without a full page reload.

[MarcHabers]

un dev