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/terminal/mail/repo/collaborator.tmpl

@@ -32,7 +32,7 @@
         <table border="0" cellpadding="0" cellspacing="0" width="100%" style="margin:24px 0 20px; border-collapse:separate;">
           <tr>
             <td align="left">
-              <a href="{{.Link}}" style="display:inline-block; padding:11px 24px; font-size:14px; font-weight:700; color:#0d1117; text-decoration:none; background-color:#00ff41; border:2px solid #00ff41; font-family:'JetBrains Mono','Fira Code','Consolas',monospace; letter-spacing:0.5px;">$ cd repo/ &amp;&amp; ls</a>
+              <a href="{{.Link}}" style="display:inline-block; padding:11px 24px; font-size:14px; font-weight:700; color:#0d1117; text-decoration:none; background-color:#00ff41; border:2px solid #00ff41; font-family:'JetBrains Mono','Fira Code','Consolas',monospace; letter-spacing:0.5px;">{{.locale.Tr "mail.view_it_on" AppName}}</a>
             </td>
           </tr>
         </table>