fix: font sizes 21/25/17px, icon labels on send btn, no-wrap fix

- Sync preload script font sizes to match app.js (21/25/17px)
- Send button variants now show icons: ↑ Send, 📝 Note, ⚡ Run
- Remove fixed width on send-col; add white-space:nowrap + padding
  so "📝 Note" never wraps regardless of font size

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/static/app.js

@@ -74,7 +74,7 @@
             otr:   { icon: '🔒', label: 'OTR' },
             agent: { icon: '⚡', label: 'Agent' },
         };
-        const send_labels = { chat: 'Send', note: 'Add Note', otr: 'Send', agent: 'Run' };
+        const send_labels = { chat: '↑ Send', note: '📝 Note', otr: '↑ Send', agent: '⚡ Run' };
 
         let current_mode = localStorage.getItem('current_mode') || 'chat';
         let note_public  = false;
@@ -1096,7 +1096,7 @@
         // ── Font size cycle ───────────────────────────────────────────
         const fontSizeBtn = document.getElementById('font-size-btn');
         const fontSizes   = ['normal', 'large', 'small'];
-        const fontSizePx  = { normal: '17px', large: '19px', small: '15px' };
+        const fontSizePx  = { normal: '21px', large: '25px', small: '17px' };
         const fontSizeLbl = { normal: 'Aa', large: 'A+', small: 'A−' };
 
         function applyFontSize(size) {