dead-code: remove .clip-template-lint orphan + extract clipTemplateGuideBtn margin

The .clip-template-lint CSS rule was documented as a no-op alias kept in case any external reference still used it (deprecated when the shared .template-lint class with .ok/.warn modifiers took over). Grep confirms zero external references — both .ts files and index.html only mention the new .template-lint class. Deleted the rule + its 5-line comment.

Same edit moves the clipTemplateGuideBtn's margin-top:8px from inline to a .clip-template-wrap .btn-secondary descendant rule. One inline style attribute gone, and the spacing now lives next to the .clip-template-wrap definition where future readers will look for it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/index.html

@@ -103,7 +103,7 @@
                     <input type="text" id="clipFilenameTemplate" value="{date}_{part}.mp4" placeholder="{date}_{part}.mp4" class="clip-modal-template-input" oninput="updateFilenameExamples()">
                     <div id="clipTemplateHelp" class="clip-modal-hint">Platzhalter: {title} {id} {channel} {date} {part} {trim_start} {trim_end} {trim_length} {date_custom="yyyy-MM-dd"}</div>
                     <div id="clipTemplateLint" class="template-lint ok">Template-Check: OK</div>
-                    <button class="btn-secondary" id="clipTemplateGuideBtn" style="margin-top: 8px;" onclick="openTemplateGuide('clip')">Template Guide</button>
+                    <button class="btn-secondary" id="clipTemplateGuideBtn" onclick="openTemplateGuide('clip')">Template Guide</button>
                 </div>
             </div>