Update Meta "startup_commands" to "exec_commands" to avoid ambiguity

[tcaiazzi]

To improve clarity and avoid ambiguity with the ".startup" commands file, we need to change the name of the meta field "startup_commands" to "exec_commands".

The current usage of "startup_commands" may cause confusion due to its similarity with the ".startup" commands file. By renaming it to "exec_commands", we establish a clearer distinction and prevent any potential misunderstandings regarding their purpose and usage.