fix: resolve 500 errors from model returning trivial status objects (root cause + v0.2 prompt fix)

Two bugs were causing the model to return {"status":"ok"} / {"status":"ready"}
instead of structured reconstruction data, resulting in POST /api/analyse 500:

1. DOUBLE-WRAPPING BUG (lib/llm/provider.js):
   generateReconstruction() called buildPrompt(scenario) on input that was
   already a fully-built prompt string from analyseScenario(). This wrapped the
   v0.1 prompt (~5000+ chars) in another template layer, producing incomprehensible
   output that the model could not parse as structured JSON.
   Fix: Pass scenario through directly (it is ALREADY a built prompt).

2. MISSING JSON SPEC (prompts/reconstruct-v0.2.md):
   The v0.2 prompt template said 'matching the structure exactly' but never
   defined what that structure was. The model invented its own field names
   (input_classification, reasoning_mode, anchors) with snake_case instead of
   camelCase, which failed Zod validation -> 500 errors.
   Fix: Added explicit JSON schema section with exact key names, enum values,
   and nested structure matching the Zod validation layer.

Additionally:
- Refactored route to use analyseScenario from lib/analysis (centralized)
- Added lib/analysis.js with shared analysis logic
- Updated components to display promptVersion and validation errors
- Added lib/reconstruction/prompt.js v0.1/v0.2 versioning
- Added lib/reconstruction/schema.js v0.2 Zod schemas
- Added debug tool scripts, evaluation results, and comparison findings

components/diagnostics-view.jsx

@@ -16,9 +16,19 @@ const ValidationIndicator = ({ status }) => {
   );
 };
 
+const validationIcons = {
+  valid: "✅",
+  partial: "⚠️",
+  invalid: "❌",
+};
+
 export default function DiagnosticsView({ result }) {
+  if (!result) return null;
+
   const metrics = [
     { label: "Model", value: result.modelName || "?" },
+    { label: "Provider", value: "Ollama" },
+    { label: "Prompt version", value: result.promptVersion || "?" },
     { label: "Duration", value: result.responseDurationMs != null ? `${result.responseDurationMs}ms` : "?" },
     { label: "Validation", value: <ValidationIndicator status={result.validationStatus || "invalid"} /> },
   ];
@@ -35,16 +45,31 @@ export default function DiagnosticsView({ result }) {
         ))}
       </dl>
 
+      {/* Collapsed raw output for debugging */}
       {result.rawResponse && (
         <details className="mt-4">
           <summary className="cursor-pointer text-xs text-gray-500 underline hover:text-gray-700">
-            View raw model response
+            View raw model response ({(result.rawResponse?.length || 0).toLocaleString()} chars)
           </summary>
           <pre className="mt-2 max-h-60 overflow-auto rounded bg-gray-900 px-3 py-2 text-xs leading-relaxed text-green-400">
             {result.rawResponse}
           </pre>
         </details>
       )}
+
+      {/* Errors if present */}
+      {result.errors && result.errors.length > 0 && (
+        <details className="mt-3">
+          <summary className="cursor-pointer text-xs text-red-500 underline hover:text-red-700">
+            Validation errors ({result.errors.length})
+          </summary>
+          <ul className="mt-1 space-y-0.5 text-xs text-red-600">
+            {result.errors.map((err, i) => (
+              <li key={i}>{err}</li>
+            ))}
+          </ul>
+        </details>
+      )}
     </div>
   );
 }