Add “Copy Source” to markup comment menu (#36726)

Any user with **read access** to a comment can now copy its raw markdown
source via the `···` context menu — no edit permission required.

Closes #36722.

---------

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

templates/repo/issue/view_content.tmpl

@@ -52,7 +52,7 @@
 								<span class="no-content">{{ctx.Locale.Tr "repo.issues.no_content"}}</span>
 							{{end}}
 						</div>
-						<div id="issue-{{.Issue.ID}}-raw" class="raw-content tw-hidden">{{.Issue.Content}}</div>
+						<div id="{{.Issue.HashTag}}-raw" class="raw-content tw-hidden">{{.Issue.Content}}</div>
 						<div class="edit-content-zone tw-hidden" data-update-url="{{$.RepoLink}}/issues/{{.Issue.Index}}/content" data-content-version="{{.Issue.ContentVersion}}" data-context="{{.RepoLink}}" data-attachment-url="{{$.RepoLink}}/issues/{{.Issue.Index}}/attachments" data-view-attachment-url="{{$.RepoLink}}/issues/{{.Issue.Index}}/view-attachments"></div>
 						{{if .Issue.Attachments}}
 							{{template "repo/issue/view_content/attachments" dict "Attachments" .Issue.Attachments "RenderedContent" .Issue.RenderedContent}}