feat(confidence-engine): add CE-ULI-08 two-condition uncertainty comparison apparatus

Adds experimental apparatus for testing whether removing the question field
from importantUnknowns in reconstruction output improves semantic fidelity.

New files:
- lib/reconstruction/schema-variant.js (conditionB schema + production passthrough)
- prompts/reconstruct-v0.5-b-noreq.md (alt prompt, identical line count to prod)

Changed files:
- lib/graph/orchestrator.js (pass generationSchema through dependencies)
- lib/analysis.js (accept opts.generationSchema fallback to original schema)
- scripts/start-case-experiment-helper.cjs (--condition B/A flag support)
- tests/scripts/start-case-experiment-helper.test.js (8 new deterministic tests)

43 targeted deterministic tests PASS. Production callers use original prompt/schema unchanged.
No live model calls. No full suite evidence available.

Co-Authored-By: Claude Code <noreply@anthropic.com>

lib/graph/orchestrator.js

@@ -370,6 +370,9 @@ export async function startCase(body, dependencies = {}) {
   if (dependencies.reconstructionModelName) {
     analysisOptions.reconstructionModelName = dependencies.reconstructionModelName;
   }
+  if (dependencies.generationSchema) {
+    analysisOptions.generationSchema = dependencies.generationSchema;
+  }
   const analysis = await analyseScenario(scenario, analysisOptions);
 
   if (!analysis.success) {