Move tabs into the header, fix Conditions ahead overflow

The tab bar was its own grid row costing about 70 px of vertical space on
every tab to hold five buttons, which is a poor trade on a layout that refuses
to scroll. The tablist now sits in the header between the title and the status
block, so the shell drops from three rows to two.

That space goes to the pressure tendency chart, which was 56 px and had no
room for Chart.js to lay out its tick row: measured, the caption sat 2 px below
its own card. The chart is now 80 px with explicit layout padding, and the
column has 11 px of slack instead of overflowing.

Also made the tendency x-axis adaptive. Hour-only labels collapsed to three
identical ticks on a short window, which is what a young station always has.
Below a six hour span the label now carries minutes.

Verified at 1600x900: Live, History, Models and Nerd all zero scrollbars, zero
clipping, zero console errors. Tabs stay reachable and the header stays one row
at 1280 and 1024 wide. Methods improved incidentally, from 68 px of overflow
to 4.

ashvale/dashboard.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""The dashboard: five tabs, one viewport, no scrolling.
+"""The dashboard: five tabs in the header, one viewport, no scrolling.
 
 Layout contract. The page is a fixed three-row grid pinned to the
 viewport height: header, tab bar, then a content region that takes the
@@ -94,10 +94,13 @@ DASHBOARD_HTML = r"""
   <div class="absolute bottom-10 left-10 w-[400px] h-[400px] bg-amber-600/10 rounded-full blur-[100px]"></div>
 </div>
 
-<div id="shell" class="max-w-[1600px] mx-auto px-3 sm:px-5 py-3 grid grid-rows-[auto_auto_1fr] gap-3 min-h-0">
+<div id="shell" class="max-w-[1600px] mx-auto px-3 sm:px-5 py-3 grid grid-rows-[auto_1fr] gap-3 min-h-0">
 
-  <header class="glass rounded-2xl px-4 py-2.5 flex flex-wrap items-center justify-between gap-3">
+  <!-- Tabs live in the header rather than a row of their own. That row cost about
-    <div class="flex items-center gap-3">
+       70 px of vertical space on every tab for five buttons, which is a poor
+       trade on a layout that refuses to scroll. -->
+  <header class="glass rounded-2xl px-4 py-2 flex flex-wrap items-center gap-x-4 gap-y-2">
+    <div class="flex items-center gap-3 shrink-0">
       <div class="p-2 bg-gradient-to-tr from-indigo-500/20 to-emerald-500/20 border border-white/10 rounded-xl">
         <svg class="w-5 h-5 text-indigo-400" fill="none" stroke="currentColor" viewBox="0 0 24 24">
           <path stroke-linecap="round" stroke-linejoin="round" stroke-width="1.8"
@@ -111,7 +114,15 @@ DASHBOARD_HTML = r"""
         </p>
       </div>
     </div>
-    <div class="flex items-center gap-2 font-mono text-[11px]">
+    <nav role="tablist" class="flex gap-1 flex-1 min-w-0 overflow-x-auto justify-center">
+      <button role="tab" data-tab="live"     aria-selected="true"  class="tabbtn shrink-0 px-3 py-1.5 rounded-lg text-[11px] font-semibold text-slate-400 border border-transparent hover:text-slate-200">Live</button>
+      <button role="tab" data-tab="history"  aria-selected="false" class="tabbtn shrink-0 px-3 py-1.5 rounded-lg text-[11px] font-semibold text-slate-400 border border-transparent hover:text-slate-200">History</button>
+      <button role="tab" data-tab="models"   aria-selected="false" class="tabbtn shrink-0 px-3 py-1.5 rounded-lg text-[11px] font-semibold text-slate-400 border border-transparent hover:text-slate-200">Models and Calibration</button>
+      <button role="tab" data-tab="nerd"     aria-selected="false" class="tabbtn shrink-0 px-3 py-1.5 rounded-lg text-[11px] font-semibold text-slate-400 border border-transparent hover:text-slate-200">Stats for Nerds</button>
+      <button role="tab" data-tab="methods"  aria-selected="false" class="tabbtn shrink-0 px-3 py-1.5 rounded-lg text-[11px] font-semibold text-slate-400 border border-transparent hover:text-slate-200">Methods</button>
+    </nav>
+
+    <div class="flex items-center gap-2 font-mono text-[11px] shrink-0">
       <span id="hd-health" class="px-2 py-1 rounded-lg border bg-slate-500/15 text-slate-300 border-slate-500/20 uppercase font-semibold">health</span>
       <span class="flex items-center gap-1.5 bg-slate-900/80 px-2.5 py-1 rounded-lg border border-slate-800">
         <span id="hd-pulse" class="w-1.5 h-1.5 rounded-full bg-emerald-400 animate-pulse"></span>
@@ -120,13 +131,6 @@ DASHBOARD_HTML = r"""
     </div>
   </header>
 
-  <nav role="tablist" class="glass rounded-2xl p-1.5 flex gap-1.5 overflow-x-auto">
-    <button role="tab" data-tab="live"     aria-selected="true"  class="tabbtn shrink-0 px-4 py-2 rounded-xl text-xs font-semibold text-slate-400 border border-transparent hover:text-slate-200">Live</button>
-    <button role="tab" data-tab="history"  aria-selected="false" class="tabbtn shrink-0 px-4 py-2 rounded-xl text-xs font-semibold text-slate-400 border border-transparent hover:text-slate-200">History</button>
-    <button role="tab" data-tab="models"   aria-selected="false" class="tabbtn shrink-0 px-4 py-2 rounded-xl text-xs font-semibold text-slate-400 border border-transparent hover:text-slate-200">Models and Calibration</button>
-    <button role="tab" data-tab="nerd"     aria-selected="false" class="tabbtn shrink-0 px-4 py-2 rounded-xl text-xs font-semibold text-slate-400 border border-transparent hover:text-slate-200">Stats for Nerds</button>
-    <button role="tab" data-tab="methods"  aria-selected="false" class="tabbtn shrink-0 px-4 py-2 rounded-xl text-xs font-semibold text-slate-400 border border-transparent hover:text-slate-200">Methods</button>
-  </nav>
 
   <main class="min-h-0">
 
@@ -256,8 +260,8 @@ DASHBOARD_HTML = r"""
             <span class="text-[10px] text-slate-500 font-mono">pressure, last 24 h</span>
             <span id="c-tend" class="text-[10px] text-violet-300 font-mono">--</span>
           </div>
-          <div class="h-14 relative"><canvas id="tendChart"></canvas></div>
+          <div class="h-20 relative"><canvas id="tendChart"></canvas></div>
-          <p class="text-[9px] text-slate-600 font-mono mt-1 leading-snug">The only signal that sees past your walls. Its slope drives the forecast.</p>
+          <p class="text-[9px] text-slate-600 font-mono mt-0.5 leading-none">Slope, not level, drives the forecast.</p>
         </div>
       </div>
     </div>
@@ -606,7 +610,7 @@ function applyPrecip(p) {
   // decide which glyph honestly represents it.
   const wx = wxPick(p.condition, lastDerived.cloud_index, lastDerived.solar_elevation,
                     lastDerived.temperature, p.rain_probability);
-  el('c-icon').innerHTML = wxSvg(wx[0], 56);
+  el('c-icon').innerHTML = wxSvg(wx[0], 44);
   el('c-sky').innerText = wx[1];
   el('c-z').innerText = p.zambretti_z!==undefined ? p.zambretti_z : '-';
   el('c-trend').innerText = p.pressure_characteristic||'-';
@@ -663,9 +667,24 @@ charts.tend = new Chart(el('tendChart').getContext('2d'), {
   data:{ datasets:[{ data:[], borderColor:'#a78bfa', backgroundColor:'rgba(167,139,250,.12)',
     fill:true, borderWidth:1.6, pointRadius:0, tension:.3, parsing:false }] },
   options:{ responsive:true, maintainAspectRatio:false, animation:false,
-    scales:{ x:{ type:'linear', grid:{display:false}, ticks:{ color:'#475569', font:{family:'JetBrains Mono',size:8}, maxTicksLimit:4,
+    // Chart.js lays the tick row out inside the canvas. At the old 56 px there
-        callback:v=>new Date(v*1000).toLocaleTimeString([], {hour:'2-digit'}) } },
+    // was not enough of it left, so the labels crowded the edge and the caption
-      y:{ grid:{color:GRID}, ticks:{ color:'#a78bfa', font:{family:'JetBrains Mono',size:8}, maxTicksLimit:4, callback:v=>v.toFixed(0) } } },
+    // spilled past the card. The layout padding reserves that strip explicitly.
+    layout:{ padding:{ bottom:2, left:2, right:4 } },
+    scales:{ x:{ type:'linear', grid:{display:false},
+        ticks:{ color:'#64748b', font:{family:'JetBrains Mono',size:9}, maxTicksLimit:4,
+        maxRotation:0, minRotation:0, padding:2,
+        // Hour-only labels collapse to three identical ticks when the window is
+        // short, which happens on a young station. Add minutes below six hours.
+        callback:function (v) {
+          const sc = this.chart.scales.x;
+          const span = (sc.max - sc.min) || 0;
+          const opts = span > 6 * 3600
+            ? {hour: '2-digit'}
+            : {hour: '2-digit', minute: '2-digit'};
+          return new Date(v * 1000).toLocaleTimeString([], opts);
+        } } },
+      y:{ grid:{color:GRID}, ticks:{ color:'#a78bfa', font:{family:'JetBrains Mono',size:9}, maxTicksLimit:4, padding:2, callback:v=>v.toFixed(0) } } },
     plugins:{ legend:{display:false}, tooltip:{ backgroundColor:'rgba(15,23,42,.95)', titleFont:MONO,
       callbacks:{ title:i=>tsFmt(i[0].parsed.x) } } } }
 });