feat: add configurable web_fetch maxChars cap

src/config/types.tools.ts

@@ -361,6 +361,8 @@ export type ToolsConfig = {
       enabled?: boolean;
       /** Max characters to return from fetched content. */
       maxChars?: number;
+      /** Hard cap for maxChars (tool or config), defaults to 50000. */
+      maxCharsCap?: number;
       /** Timeout in seconds for fetch requests. */
       timeoutSeconds?: number;
       /** Cache TTL in minutes for fetched content. */