appview/pages: swap all star buttons for same repository

On timeline, if there is multiple cards for same repository including a
star button, when user star/unstar the repository, only first `#starBtn`
is swapped with new button.

This can be fixed by adding `data-star-subject-at` attr to identify all
star buttons related to same repository and use `hx-swap-oob` to replace
all of them.

Signed-off-by: Seongmin Lee <[e-mail]>

appview/pages/templates/fragments/starBtn.html

···
     <button
         id="starBtn"
         class="btn disabled:opacity-50 disabled:cursor-not-allowed flex gap-2 items-center group"
+        data-star-subject-at="{{ .SubjectAt }}"
         {{ if .IsStarred }}
             hx-delete="/star?subject={{ .SubjectAt }}&countHint={{ .StarCount }}"
         {{ else }}
···
         hx-trigger="click"
         hx-target="this"
         hx-swap="outerHTML"
+        hx-swap-oob='outerHTML:#starBtn[data-star-subject-at="{{ .SubjectAt }}"]'
         hx-disabled-elt="#starBtn"
     >
         {{ if .IsStarred }}