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

evaluation-results/2026-08-01T06-11-41/diag-04-summary.md

@@ -0,0 +1,25 @@
+# Diagnostic Case: diag-04
+
+Decision request — forward-looking, needs missing info identification.
+
+## Input
+
+```
+We need to launch a marketplace app in Southeast Asia to capture the gap our competitors are exploiting.
+```
+
+## Result
+
+- **Technical**: ❌ FAIL (0/4 sub-checks pass)
+- **Reasoning Quality**: ❌ FAIL (0/2 sub-checks pass)
+- **Actual Primary Type**: N/A
+- **Actual Reasoning Modes**: N/A
+- **Response Duration**: 48851ms
+
+### Technical Failures
+
+schema invalid, classification mismatch, no next question
+
+### Reasoning Quality Failures
+
+