fix: make strict validation errors throw instead of returning error responses

When strictInputSchemaValidation is enabled, validation errors now properly
throw (reject the request) instead of being caught and returned as error
responses with isError: true.

Changes:
- Add strictInputSchemaValidation field to RegisteredTool type
- Store strictInputSchemaValidation flag when creating tools
- Modify error handling to rethrow validation errors when strict mode enabled

This ensures tools with strict validation fail fast on invalid input,
maintaining backwards compatibility for tools without strict validation
where errors are returned as error responses.

Changes linted and tested.

<em>🤖 Created with Claude Code via Airchat</em>

Author: Adam Bloomston

src/server/mcp.ts

@@ -174,6 +174,15 @@ export class McpServer {
                     }
                 }
             } catch (error) {
+                if (
+                    tool &&
+                    tool.strictInputSchemaValidation &&
+                    error instanceof McpError &&
+                    error.code === ErrorCode.InvalidParams &&
+                    error.message.includes('Input validation error')
+                ) {
+                    throw error;
+                }
                 return this.createToolError(error instanceof Error ? error.message : String(error));
             }
 
@@ -665,6 +674,7 @@ export class McpServer {
             outputSchema: outputSchema === undefined ? undefined : z.object(outputSchema),
             annotations,
             _meta,
+            strictInputSchemaValidation,
             callback,
             enabled: true,
             disable: () => registeredTool.update({ enabled: false }),
@@ -1035,6 +1045,7 @@ export type RegisteredTool = {
     outputSchema?: AnyZodObject;
     annotations?: ToolAnnotations;
     _meta?: Record<string, unknown>;
+    strictInputSchemaValidation?: boolean;
     callback: ToolCallback<undefined | ZodRawShape>;
     enabled: boolean;
     enable(): void;