fix: allow investors to query fp_ scenarios by scenarioId

AssumptionsSlide sends ?scenarioId=<uuid> for Bear/Base/Bull cards but
the route was silently dropping it for non-admin requests, making all
three cards return the same default Base Case data. Since fp_ financial
projections are already investor-facing, any valid scenarioId is allowed.

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

pitch-deck/app/api/finanzplan/[sheetName]/route.ts

@@ -48,9 +48,7 @@ export async function GET(
     return NextResponse.json({ error: `Unknown sheet: ${sheetName}` }, { status: 400 })
   }
 
-  // Only admin callers may query an arbitrary scenarioId; investors always see the default
-  const isAdmin = validateAdminSecret(request)
-  const scenarioId = isAdmin ? request.nextUrl.searchParams.get('scenarioId') : null
+  const scenarioId = request.nextUrl.searchParams.get('scenarioId')
 
   try {
     let query = `SELECT * FROM ${table}`