included jitter correction on client

Client/udpstreamer/static/index.html

@@ -21,6 +21,12 @@
         <span id="cur-ta">A: —</span><span class="cur-sep">│</span>
         <span id="cur-tb">B: —</span><span class="cur-sep">│</span>
         <span id="cur-dt">ΔT: —</span>
+        <span id="ruler-readout" style="display:none">
+          <span class="cur-sep">│</span>
+          <span id="cur-y1">Y1: —</span><span class="cur-sep">│</span>
+          <span id="cur-y2">Y2: —</span><span class="cur-sep">│</span>
+          <span id="cur-dy">ΔY: —</span>
+        </span>
       </div>
       <span class="ctrl-label" id="lbl-window">Window:</span>
       <select id="window-select" class="ctrl-select">
@@ -28,13 +34,17 @@
         <option value="10">10 s</option><option value="30">30 s</option>
         <option value="60">60 s</option>
       </select>
-      <button id="btn-cursor" class="ctrl-btn" style="display:none">Cursor</button>
+      <button id="btn-cursor" class="ctrl-btn">Cursors</button>
+      <button id="btn-ruler" class="ctrl-btn" title="Horizontal value rulers">Rulers</button>
       <button id="btn-zoom-back" class="ctrl-btn" style="display:none">← Back</button>
       <button id="btn-zoom-fit" class="ctrl-btn">Fit</button>
       <button id="btn-csv-all" class="ctrl-btn" title="Export all signals to CSV">⬇ CSV</button>
       <button id="btn-sync-resume" class="ctrl-btn resume-btn" style="display:none">↺ Auto</button>
       <button id="btn-trigger" class="ctrl-btn">⚡ Trigger</button>
       <button id="btn-pause-global" class="ctrl-btn">⏸ Pause</button>
+      <label class="ctrl-check" title="Snap jittery inter-frame timestamps to ideal spacing (eliminates overlaps/gaps from software-dispatch jitter)">
+        <input type="checkbox" id="cb-monotonic"> Sync TS
+      </label>
     </div>
     <!-- ── Trigger bar ───────────────────────────────────────────── -->
     <div id="trigbar">
@@ -83,6 +93,7 @@
       <div class="trig-sep"></div>
       <div class="trig-group" style="gap:8px">
         <span id="trig-status-badge">IDLE</span>
+        <button id="btn-trig-force" title="Capture now, ignoring the threshold">Force</button>
         <button id="btn-trig-stop" style="display:none">Stop</button>
         <button id="btn-trig-rearm">Rearm</button>
       </div>
@@ -185,6 +196,10 @@
           <label class="vstb-lbl">V/div</label>
           <input type="number" id="vscale-vdiv" class="ctx-num" min="1e-30" step="any" value="1">
         </div>
+        <div id="vscale-offset-row" style="display:none;align-items:center;gap:4px">
+          <label class="vstb-lbl" title="Raw value at screen centre — unbounded, may lie outside the plotted range">Offset</label>
+          <input type="number" id="vscale-offset" class="ctx-num" step="any" value="0">
+        </div>
         <div id="vscale-pos-row" style="display:none;align-items:center;gap:4px">
           <label class="vstb-lbl">Pos</label>
           <input type="number" id="vscale-pos" class="ctx-num" step="0.1" value="0">
@@ -199,6 +214,8 @@
         <button id="btn-vscale-close" class="vstb-close" title="Close">✕</button>
       </div>
     </div>
+    <!-- Follows the mouse over a plot: time + per-trace values. -->
+    <div id="hover-readout" style="display:none"></div>
     <script src="/app.js"></script>
   </body>
 </html>