Add support for passing task args and hub delegation

- Extend TaskRunOptsWith args: Vec<String> in src/cli.rs to pass extra args to tasks
- Improve CLI parsing in src/main.rs:
  - Fallback parsing: on UnknownArgument or InvalidSubcommand, treat first positional as task name and rest as args
  - Forward args to tasks::run when executing a task locally (non-hub)
- Initialize empty args in setup: TaskRunOpts in src/setup.rs
- Implement arg quoting and forwarding in src/tasks.rs:
  - Build arg_command from base command and quoted args using shell_words
  - Pass arg_command to hub delegation and to local execution
  - Include arg_command in InvocationRecord
- Refactor execution path to accept external command string:
  - Update execute_task to take command: &str and use it instead of local command construction
  - Update delegate_task_to_hub to accept and forward command: &str and embed in payload
- Update activate flow to pass the computed command string to execute_task
- Adjust tests to accommodate new command parameter and behavior