Add Top Movers screener (mid-cap+, options-tradable)

New /movers page surfaces Yahoo Finance's predefined screeners
(day_gainers, day_losers, most_actives, most_shorted_stocks)
filtered to common equities with market cap >= $2B, so every
listed name has a deep options chain. Per-row actions jump
straight into Chain / Vol Surface / IV Spike Scanner, or pin
the symbol to the Tracker watchlist.

- datafetch.ts: fetchMovers(category, count) using yf.screener,
  post-filtered to quoteType=EQUITY and marketCap >= $2B
- options.ts: GET /api/movers?category=&count=
- movers.html: Tabler page with 4-tab segmented control, sortable
  table, summary cards, volume-vs-avg ratio highlighting hot names
- All page sidebars: insert "Movers" link between Vol Surface
  and Scanner

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

frontend/scanner.html

@@ -48,7 +48,7 @@
             <li class="nav-item"><a class="nav-link" href="index.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><rect x="4" y="4" width="6" height="5" rx="2"/><rect x="4" y="13" width="6" height="7" rx="2"/><rect x="14" y="4" width="6" height="11" rx="2"/><rect x="14" y="19" width="6" height="1" rx=".5"/></svg></span><span class="nav-link-title">Dashboard</span></a></li>
             <li class="nav-item"><a class="nav-link" href="chain.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><rect x="3" y="5" width="18" height="14" rx="2"/><path d="M3 10l18 0"/><path d="M10 5v14"/></svg></span><span class="nav-link-title">Options Chain</span></a></li>
             <li class="nav-item"><a class="nav-link" href="surface.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path d="M3 12c1.333 -4.667 2.667 -7 4 -7s2.667 2.333 4 7s2.667 7 4 7s2.667 -2.333 4 -7"/></svg></span><span class="nav-link-title">Vol Surface</span></a></li>
-            <li class="nav-item active"><a class="nav-link" href="scanner.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><circle cx="11" cy="11" r="7"/><line x1="21" y1="21" x2="16.65" y2="16.65"/><path d="M11 8v6"/><path d="M8 11h6"/></svg></span><span class="nav-link-title">Scanner</span></a></li>
+            <li class="nav-item"><a class="nav-link" href="movers.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path d="M3 17l6 -6l4 4l8 -8"/><path d="M14 7l7 0l0 7"/></svg></span><span class="nav-link-title">Movers</span></a></li>            <li class="nav-item active"><a class="nav-link" href="scanner.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><circle cx="11" cy="11" r="7"/><line x1="21" y1="21" x2="16.65" y2="16.65"/><path d="M11 8v6"/><path d="M8 11h6"/></svg></span><span class="nav-link-title">Scanner</span></a></li>
             <li class="nav-item"><a class="nav-link" href="strategy.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path d="M4 19l4 -6l4 2l4 -8l4 5"/><path d="M4 4v16h16"/></svg></span><span class="nav-link-title">Strategy P/L</span></a></li>
             <li class="nav-item"><a class="nav-link" href="positions.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><rect x="3" y="7" width="18" height="13" rx="2"/><path d="M8 7v-2a2 2 0 0 1 2 -2h4a2 2 0 0 1 2 2v2"/><line x1="12" y1="12" x2="12" y2="12.01"/><path d="M3 13a20 20 0 0 0 18 0"/></svg></span><span class="nav-link-title">Positions</span></a></li>
             <li class="nav-item"><a class="nav-link" href="tracker.html"><span class="nav-link-icon d-md-none d-lg-inline-block"><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="1"/><circle cx="12" cy="12" r="5"/><circle cx="12" cy="12" r="9"/><path d="M15 12l-3 -3"/></svg></span><span class="nav-link-title">Tracker</span></a></li>