fix(feedback): theme buttons, badge the Info button, simplify admin actions

- style the About feedback button and the form's Send/attach/remove buttons with
  the accent/border tokens used by the New Game CTA, so they follow light/dark
  theme (the previous .btn/.ghost classes were not defined globally); the attach
  button is a neutral 📎 icon button with an aria-label
- show a round badge on the About 'Feedback' button when a reply is waiting
- admin: one 'ban from feedback' checkbox shared by Delete and Delete-all (via
  button formaction); hide Mark read when already read and Archive when archived
- e2e: match the About button by substring (its name gains the badge)

backend/internal/adminconsole/templates/pages/feedback_detail.gohtml

@@ -31,15 +31,14 @@
 </form>
 </section>
 <section class="panel"><h2>Actions</h2>
-<form class="form" method="post" action="/_gm/feedback/{{.ID}}/read"><button type="submit">Mark read</button></form>
-<form class="form" method="post" action="/_gm/feedback/{{.ID}}/archive"><button type="submit">Archive</button></form>
+{{if not .Read}}<form class="form" method="post" action="/_gm/feedback/{{.ID}}/read"><button type="submit">Mark read</button></form>{{end}}
+{{if not .Archived}}<form class="form" method="post" action="/_gm/feedback/{{.ID}}/archive"><button type="submit">Archive</button></form>{{end}}
 <form class="form col" method="post" action="/_gm/feedback/{{.ID}}/delete">
 <label><input type="checkbox" name="block" value="1"> ban the player from feedback</label>
-<div><button type="submit">Delete</button></div>
-</form>
-<form class="form col" method="post" action="/_gm/feedback/{{.ID}}/delete-all">
-<label><input type="checkbox" name="block" value="1"> ban the player from feedback</label>
-<div><button type="submit">Delete all from this player</button></div>
+<div>
+<button type="submit">Delete</button>
+<button type="submit" formaction="/_gm/feedback/{{.ID}}/delete-all">Delete all from this player</button>
+</div>
 </form>
 </section>
 {{end}}