Migrate `gap` helpers to tailwind (#30034)

Commands ran:

```sh
perl -p -i -e 's#gt-gap-0#tw-gap-0#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-1#tw-gap-0.5#g' web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-2#tw-gap-1#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-3#tw-gap-2#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-4#tw-gap-4#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-5#tw-gap-8#g'   web_src/js/**/* templates/**/*

perl -p -i -e 's#gt-gap-x-0#tw-gap-x-0#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-x-1#tw-gap-x-0.5#g' web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-x-2#tw-gap-x-1#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-x-3#tw-gap-x-2#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-x-4#tw-gap-x-4#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-x-5#tw-gap-x-8#g'   web_src/js/**/* templates/**/*

perl -p -i -e 's#gt-gap-y-0#tw-gap-y-0#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-y-1#tw-gap-y-0.5#g' web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-y-2#tw-gap-y-1#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-y-3#tw-gap-y-2#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-y-4#tw-gap-y-4#g'   web_src/js/**/* templates/**/*
perl -p -i -e 's#gt-gap-y-5#tw-gap-y-8#g'   web_src/js/**/* templates/**/*

3 files changed, 2 insertions, 23 deletions

diff --git a/web_src/css/helpers.css b/web_src/css/helpers.css
index 2d6bd576ae..c9c051faf4 100644
--- a/web_src/css/helpers.css
+++ b/web_src/css/helpers.css
@@ -142,27 +142,6 @@ Gitea's private styles use `g-` prefix.
 .gt-py-4 { padding-top: 1rem !important; padding-bottom: 1rem !important; }
 .gt-py-5 { padding-top: 2rem !important; padding-bottom: 2rem !important; }
 
-.gt-gap-0 { gap: 0 !important; }
-.gt-gap-1 { gap: .125rem !important; }
-.gt-gap-2 { gap: .25rem !important; }
-.gt-gap-3 { gap: .5rem !important; }
-.gt-gap-4 { gap: 1rem !important; }
-.gt-gap-5 { gap: 2rem !important; }
-
-.gt-gap-x-0 { column-gap: 0 !important; }
-.gt-gap-x-1 { column-gap: .125rem !important; }
-.gt-gap-x-2 { column-gap: .25rem !important; }
-.gt-gap-x-3 { column-gap: .5rem !important; }
-.gt-gap-x-4 { column-gap: 1rem !important; }
-.gt-gap-x-5 { column-gap: 2rem !important; }
-
-.gt-gap-y-0 { row-gap: 0 !important; }
-.gt-gap-y-1 { row-gap: .125rem !important; }
-.gt-gap-y-2 { row-gap: .25rem !important; }
-.gt-gap-y-3 { row-gap: .5rem !important; }
-.gt-gap-y-4 { row-gap: 1rem !important; }
-.gt-gap-y-5 { row-gap: 2rem !important; }
-
 /*
 gt-hidden must win all other "display: xxx !important" classes to get the chance to "hide" an element.
 do not use:
diff --git a/web_src/js/components/DiffCommitSelector.vue b/web_src/js/components/DiffCommitSelector.vue
index df712a2cb4..35245f2190 100644
--- a/web_src/js/components/DiffCommitSelector.vue
+++ b/web_src/js/components/DiffCommitSelector.vue
@@ -240,7 +240,7 @@ export default {
           @click.meta.exact="commitClicked(commit.id, true)"
           @click.shift.exact.stop.prevent="commitClickedShift(commit)"
         >
-          <div class="tw-flex-1 tw-flex tw-flex-col gt-gap-2">
+          <div class="tw-flex-1 tw-flex tw-flex-col tw-gap-1">
             <div class="gt-ellipsis commit-list-summary">
               {{ commit.summary }}
             </div>
diff --git a/web_src/js/components/RepoContributors.vue b/web_src/js/components/RepoContributors.vue
index 6de68a4aec..02db9e3e3e 100644
--- a/web_src/js/components/RepoContributors.vue
+++ b/web_src/js/components/RepoContributors.vue
@@ -384,7 +384,7 @@ export default {
             <h4 v-else class="contributor-name">
               {{ contributor.name }}
             </h4>
-            <p class="tw-text-12 tw-flex gt-gap-2">
+            <p class="tw-text-12 tw-flex tw-gap-1">
               <strong v-if="contributor.total_commits">{{ contributor.total_commits.toLocaleString() }} {{ locale.contributionType.commits }}</strong>
               <strong v-if="contributor.total_additions" class="text green">{{ contributor.total_additions.toLocaleString() }}++ </strong>
               <strong v-if="contributor.total_deletions" class="text red">