feat: add hook config support

[PeterCardenas]

Closes #144

Add support for specifying hookConfigs when creating a session to react to hook events.

Hooks are specified with the following type:

export type HookConfig = {
  /** The hook event to listen for */
  event: HookEvent;
  /** 
   * Optional matcher string to filter which tools trigger this hook.
   * Only relevant for tool-related hooks: PreToolUse, PostToolUse, PostToolUseFailure, PermissionRequest
   */
  matcher?: string;
  /** Command to execute */
  command: string;
  /** Arguments for the command */
  args?: string[];
  /** Environment variables to pass to the command */
  env?: Record<string, string>;
};

These commands are executed with environment variables populated with the tool input, so arguments or the command itself can handle the input accordingly.
To give hook output, the command must print, and only print, a JSON string to stdout which will be parsed to use as the hook result. Otherwise, the agent will continue.

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[PeterCardenas]

@cla-bot check

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