fix(ui): ensure same width of usercards in grid (#6799)

Followup to https://codeberg.org/forgejo/forgejo/pulls/4760

* some refactoring
    * move rules out of repo.css to a new module
    * simplify selectors by omitting .list: it is now only used to style the list itself, they're still precise enough in scope of .user-cards
* apply wrap/ellipsis to cards' content. Done via CSS to avoid spamming gt-ellipsis in the template
    * prevent cards with long content from taking horizontal space from other cards
    * prevent such cards from causing horizontal overflow on mobile
    * prevent varying card height, it doesn't look good even with text wrapping

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/6799
Reviewed-by: Otto <otto@codeberg.org>
Co-authored-by: 0ko <0ko@noreply.codeberg.org>
Co-committed-by: 0ko <0ko@noreply.codeberg.org>

models/fixtures/follow.yml

@@ -17,3 +17,13 @@
   id: 4
   user_id: 31
   follow_id: 33
+
+-
+  id: 5
+  user_id: 4
+  follow_id: 8
+
+-
+  id: 6
+  user_id: 5
+  follow_id: 8

models/fixtures/user.yml

@@ -53,6 +53,7 @@
   login_source: 0
   login_name: user2
   type: 0
+  website: https://keyoxide.org/eb114f5e6c0dc2bcdd183550a4b61a2dc5923710
   salt: ZogKvWdyEx
   max_repo_creation: -1
   is_active: true
@@ -143,7 +144,7 @@
   avatar_email: user4@example.com
   use_custom_avatar: true
   num_followers: 0
-  num_following: 1
+  num_following: 2
   num_stars: 0
   num_repos: 0
   num_teams: 0
@@ -181,7 +182,7 @@
   avatar_email: user5@example.com
   use_custom_avatar: true
   num_followers: 0
-  num_following: 0
+  num_following: 1
   num_stars: 0
   num_repos: 1
   num_teams: 0
@@ -294,7 +295,7 @@
   avatar: ""
   avatar_email: user8@example.com
   use_custom_avatar: true
-  num_followers: 1
+  num_followers: 3
   num_following: 1
   num_stars: 0
   num_repos: 0