## Why
Building MCP search entries eagerly cloned tool specs and normalized schemas even for tools that were never selected.
## What changed
Store search specs in `Arc<ToolSpec>` and let MCP search entries share the handler's spec. Materialize and normalize loadable specs only for selected results, preserving existing result formatting and dynamic-tool cache equality behavior.
## Testing
Add coverage for function, freeform, and namespace specs that verifies shared specs produce equivalent results, retain the source while needed, and release it when the search entry is dropped.
GitOrigin-RevId: 4260f2e2527834d8a856b1528654c6951aab8a7d