Drop question-report entirely, obfuscate the mailto link instead

The report button logged to an event stream nothing ever read - no
notification, no dashboard, just a durable no-op. A browser back
button already covers "this page wasn't helpful" better than a button
that silently does nothing visible to anyone but the visitor who
clicked it.

The mailto address is now assembled from data-user/data-domain on a
real mouse event instead of baked into the server-rendered href -
keeps a plain mailto: string (what bulk scrapers regex HTML for) out
of what a generic bot crawl sees, without hiding the contact option
from an actual visitor.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/content.rs

@@ -21,10 +21,8 @@ pub struct Question {
     pub qualifies: Option<String>,
     #[serde(default)]
     pub alternatives: Vec<Alternative>,
-    /// Who to contact if a visitor gets stuck or finds this question
-    /// unhelpful - rendered as a small line on the page, and the person
-    /// a "report this question" action names in its own event payload
-    /// (see `events::store`, `question_report` aggregate-less events).
+    /// Who to contact if a visitor gets stuck - rendered as a small line
+    /// on the page.
     #[serde(default)]
     pub responsible: Option<Responsible>,
 }