Fix pipeline edit crash: merge defaults with DB configJson

The DB configJson uses different field names than wizard types expect
(e.g., deterministic.rules vs rules, votingEnabled vs juryVotingEnabled).
The ?? operator only guards null/undefined, but configJson is {} (truthy),
so defaults never applied. This caused config.rules.map() to crash with
"Cannot read properties of undefined (reading 'map')".

Fix: spread defaults first then overlay DB values, and add defensive ??
fallbacks in all section components for potentially undefined properties.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/(admin)/admin/rounds/pipeline/[id]/edit/page.tsx

@@ -187,10 +187,10 @@ export default function EditPipelinePage() {
   const evalStage = mainTrack?.stages.find((s) => s.stageType === 'EVALUATION')
   const liveStage = mainTrack?.stages.find((s) => s.stageType === 'LIVE_FINAL')
 
-  const intakeConfig = (intakeStage?.configJson ?? defaultIntakeConfig()) as unknown as IntakeConfig
-  const filterConfig = (filterStage?.configJson ?? defaultFilterConfig()) as unknown as FilterConfig
-  const evalConfig = (evalStage?.configJson ?? defaultEvaluationConfig()) as unknown as EvaluationConfig
-  const liveConfig = (liveStage?.configJson ?? defaultLiveConfig()) as unknown as LiveFinalConfig
+  const intakeConfig = { ...defaultIntakeConfig(), ...(intakeStage?.configJson ?? {}) } as IntakeConfig
+  const filterConfig = { ...defaultFilterConfig(), ...(filterStage?.configJson ?? {}) } as FilterConfig
+  const evalConfig = { ...defaultEvaluationConfig(), ...(evalStage?.configJson ?? {}) } as EvaluationConfig
+  const liveConfig = { ...defaultLiveConfig(), ...(liveStage?.configJson ?? {}) } as LiveFinalConfig
 
   const basicsValid = validateBasics(state).valid
   const tracksValid = validateTracks(state.tracks).valid