feat: Add Python consistency tests for calculator definitions and refactor QuickConversionTable to explicitly pass calculator configuration to its row builder.

hdyc-svelte/src/lib/components/QuickConversionTable.svelte

@@ -8,8 +8,8 @@
 
   type Row = { input: number; output: string };
 
-  const buildRow = (value: number): Row => {
-    const formatted = solve(config, 1, value.toString(), '', '');
+  const buildRow = (value: number, c: CalculatorDef): Row => {
+    const formatted = solve(c, 1, value.toString(), '', '');
     return {
       input: value,
       output: formatted.val2 || '—',
@@ -22,8 +22,8 @@
   let outputLabel = 'target units';
 
   $: supportsTable = ['standard', 'inverse'].includes(config.type);
-  $: rows = supportsTable
-    ? numericSamples.map(buildRow)
+  $: rows = (config && supportsTable)
+    ? numericSamples.map(v => buildRow(v, config))
     : [];
   $: inputLabel = config.labels?.in1 ?? 'source units';
   $: outputLabel = config.labels?.in2 ?? 'target units';

hdyc-svelte/src/routes/[slug]/+page.svelte

@@ -82,7 +82,9 @@
 
 <h1 class="page-title calculator-page-title">{calc.name}</h1>
 
-<Calculator config={calc} showTitle={false} />
+{#key calc.slug}
+  <Calculator config={calc} showTitle={false} />
+{/key}
 
 <div class="seo-content">
   {#if calc.descriptionHTML}