feat(chat): quote with the '>' line prefix instead of guillemets

The Quote button produced `@[user] »text« ` — a shape mc-webui invented back
when it could not send newlines, and one that other MeshCore clients neither
write nor understand. It now writes the quote on its own line behind a '>'
and leaves the cursor underneath it, matching the plain-text convention some
users already type by hand.

processQuotes() styles both syntaxes, so messages sent by older builds keep
their formatting. The '>' match is anchored to a line start or a leading
@[mention] badge and looks for the escaped '>', so neither "5 > 3" in
prose nor the brackets of generated tags can trigger it.

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

app/static/js/app.js

@@ -1531,11 +1531,15 @@ function truncateToBytes(text, maxBytes) {
 }
 
 /**
- * Insert a quote into the message input.
+ * Insert a quote into the message input, leaving the cursor on a fresh line
+ * for the reply. Uses the `>` line prefix rather than the guillemets of older
+ * versions, so the quote also reads as one in clients that don't style it.
  */
 function insertQuote(username, quotedText) {
     const input = document.getElementById('messageInput');
-    input.value = `@[${username}] »${quotedText}« `;
+    // One '>' per line — a quoted multi-line message stays fully quoted.
+    const quoted = quotedText.split('\n').map(line => `>${line}`).join('\n');
+    input.value = `@[${username}] ${quoted}\n`;
     updateCharCounter();
     input.focus();
 }

app/static/js/message-utils.js

@@ -134,18 +134,32 @@ function processChannelLinks(text) {
 }
 
 /**
- * Convert »quoted text« to styled quote blocks
+ * Convert quoted text to styled quote blocks. Two syntaxes are recognised:
+ * `>quoted line` (current, also what other MeshCore clients use) and
+ * `»quoted text«` (what mc-webui produced before 2.2.0 — still rendered so
+ * older messages keep their styling).
  * @param {string} text - HTML-escaped text
  * @returns {string} - Text with styled quotes
  */
 function processQuotes(text) {
-    // Match »...« pattern (guillemets) including optional trailing whitespace
-    const quotePattern = /»([^«]+)«\s*/g;
-
-    return text.replace(quotePattern, (_match, quoted) => {
-        // Display without guillemets (styling is enough) + line break after
+    // Legacy guillemets: the markers are dropped (styling replaces them) and
+    // the pattern eats the space separating quote from reply, hence the <br>.
+    const legacyPattern = /»([^«]+)«\s*/g;
+    text = text.replace(legacyPattern, (_match, quoted) => {
         return `<span class="quote-text">${quoted}</span><br>`;
     });
+
+    // `>quoted line`. The text arrives HTML-escaped, so a typed '>' shows up as
+    // '&gt;' and the '>' of generated tags can never match. Anchored to the
+    // start of a line or to a leading @[mention] badge, so "5 &gt; 3" mid
+    // sentence is left alone. The trailing newline stays in place — the message
+    // containers are pre-wrap and render it as the break.
+    const quotePattern = /(^|\n|<\/span>[ \t]*)&gt;[ \t]*([^\n]*)/g;
+
+    return text.replace(quotePattern, (match, prefix, quoted) => {
+        if (!quoted.trim()) return match;
+        return `${prefix}<span class="quote-text">${quoted}</span>`;
+    });
 }
 
 /**