feat: register anthropic-effort hook in plugin lifecycle

- Add "anthropic-effort" to HookNameSchema enum
- Import and create hook in plugin entry with isHookEnabled guard
- Wire chat.params event handler to invoke the effort hook
- First hook to use the chat.params lifecycle event from plugin

src/config/schema.ts

@@ -101,6 +101,7 @@ export const HookNameSchema = z.enum([
   "stop-continuation-guard",
   "tasks-todowrite-disabler",
   "write-existing-file-guard",
+  "anthropic-effort",
 ])
 
 export const BuiltinCommandNameSchema = z.enum([