Implement 'call' button

app.js

@@ -880,7 +880,131 @@ function openRefsModal(tuneId) {
   refsModal.showModal();
 }
 
-// ── Bulk Edit ─────────────────────────────────────────────
+// ── Call mode ─────────────────────────────────────────────────────
+const callModal = $('call-modal');
+let callStep         = 0;
+let callInstrumentId = null;
+let callTuningId     = null;
+
+function callableEntries() {
+  const result = [];
+  for (const tune of allTunes)
+    for (const entry of tune.instruments)
+      if (entry.callable) result.push({ tune, entry });
+  return result;
+}
+
+function callGetInstruments() {
+  const map = new Map();
+  callableEntries().forEach(({ entry }) => {
+    if (!map.has(entry.instrument_id)) map.set(entry.instrument_id, entry.instrument_name);
+  });
+  return [...map.entries()].map(([id, name]) => ({ id, name }))
+    .sort((a, b) => a.name.localeCompare(b.name));
+}
+
+function callGetTunings() {
+  const map = new Map();
+  callableEntries()
+    .filter(({ entry }) => callInstrumentId === null || entry.instrument_id === callInstrumentId)
+    .forEach(({ entry }) => {
+      if (entry.tuning_id != null && !map.has(entry.tuning_id))
+        map.set(entry.tuning_id, entry.tuning);
+    });
+  return [...map.entries()].map(([id, name]) => ({ id, name }))
+    .sort((a, b) => a.name.localeCompare(b.name));
+}
+
+function callGetKeys() {
+  const map = new Map();
+  callableEntries()
+    .filter(({ entry }) =>
+      (callInstrumentId === null || entry.instrument_id === callInstrumentId) &&
+      (callTuningId === null     || entry.tuning_id    === callTuningId)
+    )
+    .forEach(({ tune }) => {
+      if (tune.key) {
+        const k = tune.key + '|' + (tune.modal ? '1' : '0');
+        if (!map.has(k)) map.set(k, { key: tune.key, modal: !!tune.modal });
+      }
+    });
+  return [...map.values()]
+    .sort((a, b) => a.key.localeCompare(b.key) || (a.modal ? 1 : -1));
+}
+
+function openCallModal() {
+  callStep = 0;
+  callInstrumentId = null;
+  callTuningId = null;
+  renderCallStep();
+  callModal.showModal();
+}
+
+function renderCallStep() {
+  const items = callStep === 0 ? callGetInstruments()
+              : callStep === 1 ? callGetTunings()
+              : callGetKeys();
+
+  // Skip this screen if there's only one option
+  if (items.length === 1) {
+    callSelect(callStep === 2 ? items[0].key : items[0].id,
+               callStep === 2 ? items[0].modal : null);
+    return;
+  }
+
+  $('call-title').textContent = ['Instrument', 'Tuning', 'Key'][callStep];
+  $('call-back').hidden = callStep === 0;
+  const opts  = $('call-options');
+  opts.innerHTML = '';
+  const allBtn = document.createElement('button');
+  allBtn.className = 'call-option-btn call-all-btn';
+  allBtn.textContent = 'All';
+  allBtn.addEventListener('click', () => callSelect(null, null));
+  opts.appendChild(allBtn);
+  items.forEach(item => {
+    const btn = document.createElement('button');
+    btn.className = 'call-option-btn';
+    btn.textContent = callStep === 2
+      ? (item.modal ? item.key + ' modal' : item.key)
+      : item.name;
+    btn.addEventListener('click', () =>
+      callSelect(callStep === 2 ? item.key : item.id,
+                 callStep === 2 ? item.modal : null));
+    opts.appendChild(btn);
+  });
+}
+
+function callSelect(value, modal) {
+  if (callStep === 0) {
+    callInstrumentId = value;
+    callStep = 1;
+    renderCallStep();
+  } else if (callStep === 1) {
+    callTuningId = value;
+    callStep = 2;
+    renderCallStep();
+  } else {
+    filters.callable   = true;
+    filters.instrument = callInstrumentId !== null ? String(callInstrumentId) : null;
+    filters.tuning     = callTuningId     !== null ? String(callTuningId)     : null;
+    filters.key        = value;
+    filters.modal      = value !== null ? modal : null;
+    updateFilterIndicators();
+    renderTable();
+    callModal.close();
+  }
+}
+
+$('btn-call').addEventListener('click', openCallModal);
+$('call-close').addEventListener('click', () => callModal.close());
+$('call-back').addEventListener('click', () => {
+  callStep--;
+  if (callStep === 0) callInstrumentId = null;
+  else if (callStep === 1) callTuningId = null;
+  renderCallStep();
+});
+
+// ── Bulk Edit ──────────────────────────────────────────────
 btnBulkEdit.addEventListener('click', e => {
   e.stopPropagation();
   if (!bulkEditPopover.hidden) { bulkEditPopover.hidden = true; return; }