fix(viewer): 4 bugs — Plotly resize, no-data overlay, fetch overkill, tab resize

Bug1: populatePlotlyCharts now forces requestAnimationFrame Plotly.Plots.resize
      after react() so charts render correctly even after hidden/late init
Bug1b: switchTab(charts) triggers resize on all 4 chart divs
Bug2: loadSortieData calls showNoDataOverlay(false) when USV data loaded
Bug3: loadDate filters missions via availableDates cache before fetching
      all dives — avoids O(n*missions) requests when date entry known

viewer/index.html

@@ -574,6 +574,13 @@ function populatePlotlyCharts() {
   Plotly.react('chart-pwm-auv', pwmAuvTraces,  { ...layout, showlegend: pwmAuvTraces.length > 1 }, PLOTLY_CONFIG);
   Plotly.react('chart-pwm-usv', pwmUsvTraces,  { ...layout, showlegend: pwmUsvTraces.length > 1 }, PLOTLY_CONFIG);
   Plotly.react('chart-usbl',    usblDistTraces, layout,        PLOTLY_CONFIG);
+  // Force resize: Plotly can't compute size on hidden/zero-size divs at init time
+  requestAnimationFrame(() => {
+    ['chart-depth','chart-pwm-auv','chart-pwm-usv','chart-usbl'].forEach(id => {
+      const el = document.getElementById(id);
+      if (el && el._fullLayout) Plotly.Plots.resize(el);
+    });
+  });
 }
 
 // Update cursor line on all Plotly charts
@@ -744,7 +751,16 @@ async function loadDate(date) {
 
     const dateStr = date.replace(/-/g,''); // YYYYMMDD
 
-    const fetches = missions.map(async mission => {
+    // BUG3 FIX: filter missions using availableDates to avoid fetching all missions' dives
+    const dateEntry = availableDates.find(d => d.date === date);
+    const knownMissions = dateEntry && dateEntry.missions && dateEntry.missions.length
+      ? dateEntry.missions
+      : null;
+    const missionsToFetch = knownMissions
+      ? missions.filter(m => knownMissions.includes(m.id) || knownMissions.some(km => m.id.includes(km) || km.includes(m.id)))
+      : missions;
+
+    const fetches = (missionsToFetch.length > 0 ? missionsToFetch : missions).map(async mission => {
       const dResp = await fetch(`${API}/api/missions/${mission.id}/dives`);
       const dives = await dResp.json();
       return { mission, dives: dives.filter(d => d.id.startsWith(dateStr)) };
@@ -1010,6 +1026,15 @@ function switchTab(name) {
     const names = ['charts','usv','auv'];
     btn.classList.toggle('active', names[i] === name);
   });
+  // BUG1 FIX: resize Plotly charts when tab becomes visible
+  if (name === 'charts') {
+    requestAnimationFrame(() => {
+      ['chart-depth','chart-pwm-auv','chart-pwm-usv','chart-usbl'].forEach(id => {
+        const el = document.getElementById(id);
+        if (el && el._fullLayout) Plotly.Plots.resize(el);
+      });
+    });
+  }
 }
 
 // == No-data overlay ==
@@ -1202,6 +1227,7 @@ async function loadSortieData(sortieId) {
     if (usvResp.ok) {
       const usvData = await usvResp.json();
       renderUSV(usvData.signals);
+      showNoDataOverlay(false);  // BUG2 FIX: hide overlay when data loaded
     }
     prog.textContent = 'Chargement AUV…';
     await loadAuvTabs(sortieId);