feat(journal): improve sheet rendering and URL persistence

- Update SheetView to use full-width SVG and auto-height for better
  scaling
- Center template nodes in SheetView to maintain text alignment
- Enable overflow-y-auto in SheetView to support long sheets
- Persist selected sheet ID in URL search parameters in StatsView

src/components/journal/SheetView.tsx

@@ -65,8 +65,25 @@ export const SheetView: Component<{ sheetId: string }> = (props) => {
 
     container.innerHTML = "";
     const parsed = parseSheet(s.svg);
+    // Force full-width, auto-height
+    parsed.svgElement.setAttribute("width", "100%");
+    parsed.svgElement.removeAttribute("height");
+    parsed.svgElement.style.display = "block";
     container.appendChild(parsed.svgElement);
 
+    // Center template nodes so text stays centered as values change length
+    for (const tpl of parsed.templates) {
+      const el = tpl.el;
+      try {
+        const bbox = el.getBBox();
+        const cx = bbox.x + bbox.width / 2;
+        el.setAttribute("text-anchor", "middle");
+        el.setAttribute("x", String(cx));
+      } catch {
+        // getBBox may fail if the node has no layout — skip silently
+      }
+    }
+
     if (parsed.templates.length === 0) return;
 
     const dispose = createRoot((disposer) => {
@@ -93,9 +110,9 @@ export const SheetView: Component<{ sheetId: string }> = (props) => {
   );
 
   return (
-    <div class="w-full h-full flex items-center justify-center p-2">
+    <div class="w-full h-full overflow-y-auto p-2">
       {sheet() ? (
-        <div ref={containerRef} class="w-full h-full" />
+        <div ref={containerRef} class="w-full" />
       ) : (
         fallback
       )}