feat: relax outputSchema to accept non-object JSON Schema types (SEP-2106) (#895)

* fix: address PR review - schema_for_output no longer validates or returns Result

- Add strip_output() that strips title/description without validating type (Dale #1)
- Change schema_for_output to return Arc<JsonObject> instead of Result (Dale #2)
- Cache only Arc<JsonObject> success values, not Result (Dale #3)
- Remove dead unwrap_or_else panic paths in with_output_schema, ToolBase, and macros
- Tighten test assertions from contains to assert_eq on type field (Dale #4)
- Update test_schema_for_output_rejects_primitive to accept_primitive (SEP-2106)

Co-authored-by: Orca <help@stably.ai>

* test(rmcp): add non-object output schema tests for SEP-2106

Add tests verifying schema_for_output accepts non-object types:
- test_tool_builder_methods: primitive (i32), array (Vec<String>), option
- test_structured_output: tool returning Json<Vec<T>> and Json<i32>
- test_json_schema_detection: Json<Vec<T>>, Result<Json<Vec<T>>,E>, Json<String>
- tool_traits: ToolBase::output_schema with Vec<AddOutput> output type

* test(rmcp): add missing edge case tests from code review

Add tests identified during code review:
- description stripping for primitive types
- composition types (Option<String> with anyOf/oneOf/null)
- cache correctness (Arc::ptr_eq for repeated calls)
- schema_for_input rejecting array types (not just primitives)
- schema_for_output accepting unit type ()

* feat!: mark schema_for_output return-type change as breaking

This introduces SEP-2106: schema_for_output no longer validates or
returns Result. The public signature changed, so bump major.

* fix: address Dale's PR review - direct schema.get assertions, remove ArrayTool

- Replace loose schema_str.contains(...) assertions with direct
  schema.get("type") equality checks in test_tool_builder_methods.rs
  and test_structured_output.rs
- Remove redundant ArrayTool fixture and its round-trip
  serde_json::from_str test from tool_traits.rs since schema is
  already Arc<JsonObject>
- Drop dead schema_str variable in test_structured_output.rs

---------

Co-authored-by: Brandon Bennett <brandonbennett@macbookair.myfiosgateway.com>
Co-authored-by: Orca <help@stably.ai>
Co-authored-by: Brandon Bennett <brandonbennett@Pursuits-Air.lan>

crates/rmcp-macros/src/tool.rs

@@ -28,13 +28,6 @@ fn extract_schema_from_return_type(ret_type: &syn::Type) -> Option<Expr> {
     if let Some(inner_type) = extract_json_inner_type(ret_type) {
         return syn::parse2::<Expr>(quote! {
             rmcp::handler::server::tool::schema_for_output::<#inner_type>()
-                .unwrap_or_else(|e| {
-                    panic!(
-                        "Invalid output schema for Json<{}>: {}",
-                        std::any::type_name::<#inner_type>(),
-                        e
-                    )
-                })
         })
         .ok();
     }
@@ -65,13 +58,6 @@ fn extract_schema_from_return_type(ret_type: &syn::Type) -> Option<Expr> {
 
     syn::parse2::<Expr>(quote! {
         rmcp::handler::server::tool::schema_for_output::<#inner_type>()
-            .unwrap_or_else(|e| {
-                panic!(
-                    "Invalid output schema for Result<Json<{}>, E>: {}",
-                    std::any::type_name::<#inner_type>(),
-                    e
-                )
-            })
     })
     .ok()
 }