fix(encoding): replace Unicode em dashes and ellipsis with ASCII equivalents

In JS comments and string literals, replace:
- U+2014 em dash with ASCII '--'
- U+2026 ellipsis with HTML entity …

Prevents double-encoding issues consistent with project conventions (PR #38).

Author: bertheto

src/static/index.html

@@ -999,7 +999,7 @@
       setTimeout(() => target.classList.remove('msg-jump-highlight'), 1500);
     };
 
-    // UI-13: event delegation — intercepts clicks on any .msg-reply-quote in #messages
+    // UI-13: event delegation -- intercepts clicks on any .msg-reply-quote in #messages
     document.getElementById('messages')?.addEventListener('click', (e) => {
       const btn = e.target.closest('button.msg-reply-quote');
       if (!btn) return;
@@ -1206,9 +1206,9 @@
         priorityBadgeHtml = '<span class="msg-priority-badge msg-priority-system" title="System message">SYSTEM</span>';
       }
 
-      // Reply-to quote (UP-14) — UI-13: clickable button with event delegation
+      // Reply-to quote (UP-14) -- UI-13: clickable button with event delegation
       const replyQuoteHtml = m.reply_to_msg_id
-        ? `<button class="msg-reply-quote" data-reply-target="${esc(m.reply_to_msg_id)}" title="Jump to message ${esc(m.reply_to_msg_id)}">&#8617; In reply to: <em>${esc(m.reply_to_msg_id.slice(0, 8))}…</em></button>`
+        ? `<button class="msg-reply-quote" data-reply-target="${esc(m.reply_to_msg_id)}" title="Jump to message ${esc(m.reply_to_msg_id)}">&#8617; In reply to: <em>${esc(m.reply_to_msg_id.slice(0, 8))}&#8230;</em></button>`
         : '';
 
       // Edit indicator (UP-21)

src/static/js/shared-modals.js

@@ -102,7 +102,7 @@
     // UI-14: get or register a browser-session agent to provide auth for thread creation
     const uiAgent = window.AcbUiAgent ? await window.AcbUiAgent.ensureUiAgent() : null;
     if (!uiAgent) {
-      console.error("[Thread Create] Could not obtain UI agent token — cannot create thread");
+      console.error("[Thread Create] Could not obtain UI agent token -- cannot create thread");
       return;
     }
 

src/static/js/shared-ui-agent.js

@@ -10,7 +10,7 @@
         const parsed = JSON.parse(cached);
         if (parsed.agent_id && parsed.token) return parsed;
       } catch (_) {
-        // corrupted — fall through to re-register
+        // corrupted -- fall through to re-register
       }
     }