feat: sync runtime search and schema quality updates from app repo

- port retrieval, validation, and eval improvements relevant to os
- align prompts and dimensions with the flat single-agent model
- replace the old eval suite with the focused core scenarios

Generated with Codex

app/api/dimensions/[name]/context/route.ts

@@ -44,7 +44,7 @@ export async function GET(
     const context: DimensionContext = {
       name: dimension.name,
       description: dimension.description,
-      isPriority: dimension.is_priority === 1,
+      isPriority: false,
       nodeCount: countResult?.count || 0,
     };