Method register

packages/graph/src/FunctionRegistry.ts:98–101

* Register a function definition.

(def: FunctionDefinition)

   * Register a function definition.
   */
  public register(def: FunctionDefinition): void {
    // Store with lowercase name for case-insensitive lookup
    this.#functions.set(def.name.toLowerCase(), def);
  }

  /**
   * Look up a function by name (case-insensitive).