feat: terminal aesthetic rewrite + link debug page

- Full dark terminal aesthetic (Pulse/TinkerTickets style):
  - #0a0a0a background, #00ff41 green, #ffb000 amber, #00ffff cyan
  - CRT scanline overlay, phosphor glow, ASCII corner pseudoelements
  - Bracket-notation badges [CRITICAL], monospace font throughout
  - style.css, base.html, index.html, suppressions.html all rewritten

- New Link Debug page (/links, /api/links):
  - Per-host, per-interface cards with speed/duplex/port type/auto-neg
  - Traffic bars (TX cyan, RX green) with rate labels
  - Error/drop counters, carrier change history
  - SFP/DOM optical panel: vendor, temp, voltage, bias, TX/RX power dBm bars
  - RX-TX delta shown; color-coded warn/crit thresholds
  - Auto-refresh every 60s, anchor-jump to #hostname

- LinkStatsCollector in monitor.py:
  - SSHes to each host (one connection, all ifaces batched)
  - Parses ethtool + ethtool -m (SFP DOM) output
  - Merges with Prometheus traffic/error/carrier metrics
  - Stores as link_stats in monitor_state table

- config.json: added ssh section for ethtool collection
- app.js: terminal chip style consistency (uppercase, ● bullet)

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

app.py

@@ -96,6 +96,13 @@ def index():
     )
 
 
+@app.route('/links')
+@require_auth
+def links_page():
+    user = _get_user()
+    return render_template('links.html', user=user)
+
+
 @app.route('/suppressions')
 @require_auth
 def suppressions_page():
@@ -139,6 +146,18 @@ def api_network():
     return jsonify({'hosts': {}, 'unifi': [], 'updated': None})
 
 
+@app.route('/api/links')
+@require_auth
+def api_links():
+    raw = db.get_state('link_stats')
+    if raw:
+        try:
+            return jsonify(json.loads(raw))
+        except Exception:
+            pass
+    return jsonify({'hosts': {}, 'updated': None})
+
+
 @app.route('/api/events')
 @require_auth
 def api_events():