fix(templates): cross-validate against official Gitea mail templates

- Fix INK theme: replace .ActiveCodeLives with correct field, remove from non-auth contexts (8 files)
- Fix hardcoded button text: use locale key mail.view_it_on in ember, heritage, ink, mono, terminal, terra (30+ files)
- Add missing {{if .CanReply}}mail.reply{{end}} block to all 10 themes default.tmpl
- Add missing mail.release.note locale label to all 10 themes release.tmpl
- Add missing mail.team_invite.text_3 to ink and terra team_invite.tmpl
- Add missing blockquote CSS to aurora, ink, mono, neon, terra default.tmpl

Verified: all 110 templates compile successfully with Go build-preview.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

themes/bloom/mail/repo/issue/default.tmpl

@@ -65,7 +65,8 @@
           {{end}}
         {{else}}
           {{.Body}}
-        {{end -}}
+        {{end -}}{{if .CanReply}} {{.locale.Tr "mail.reply"}}{{end}}
+
         </p>
 
         {{- range .ReviewComments}}