Add infinity max option for reciprocal scale

web/templates/index.html

@@ -330,9 +330,11 @@
             <label>Min value</label>
             <input name="min" type="number" step="any" value="0" required>
           </div>
-          <div class="field">
+          <div class="field" id="field-max">
             <label>Max value</label>
-            <input name="max" type="number" step="any" value="100" required>
+            <input name="max" id="input-max" type="number" step="any" value="100" required>
+            <button type="button" id="btn-inf" style="display:none;font-family:var(--f-mono);font-size:0.65rem;color:var(--muted);background:none;border:none;padding:0;cursor:pointer;text-align:left">set max = ∞</button>
+            <input type="hidden" name="max_is_inf" id="max-is-inf" value="">
           </div>
         </div>
         <input type="hidden" name="scale_type" id="scale-type" value="linear">
@@ -397,6 +399,31 @@
   <script>
     let lastSvg = '';
 
+    function resetInf() {
+      const inp = document.getElementById('input-max');
+      const hidden = document.getElementById('max-is-inf');
+      const btn = document.getElementById('btn-inf');
+      inp.style.display = '';
+      inp.required = true;
+      hidden.value = '';
+      btn.textContent = 'set max = ∞';
+    }
+
+    document.getElementById('btn-inf').addEventListener('click', () => {
+      const inp = document.getElementById('input-max');
+      const hidden = document.getElementById('max-is-inf');
+      const btn = document.getElementById('btn-inf');
+      if (hidden.value === '1') {
+        resetInf();
+      } else {
+        inp.style.display = 'none';
+        inp.required = false;
+        hidden.value = '1';
+        btn.textContent = 'max = ∞ (click to reset)';
+      }
+      doGenerate();
+    });
+
     async function doGenerate() {
       const status = document.getElementById('status');
       status.textContent = 'Generating…';
@@ -448,6 +475,14 @@
               if (!(parseFloat(minInput.value) > 0)) minInput.value = '1';
               if (!(parseFloat(maxInput.value) > parseFloat(minInput.value))) maxInput.value = String(parseFloat(minInput.value) * 10);
             }
+            // Show/hide ∞ toggle
+            const infBtn = document.getElementById('btn-inf');
+            if (btn.dataset.scale === 'reciprocal') {
+              infBtn.style.display = '';
+            } else {
+              infBtn.style.display = 'none';
+              resetInf();
+            }
           }
           doGenerate();
         });