[BUG]: Blueprint applications launched with `--debug` do not automatically have `DEBUG` logging enabled

[asnare]

The CLI pattern enabled by App doesn't properly propagate the log-level from the command payload into the logging system. This means that the --debug flag doesn't enable DEBUG logging, which is its intent.

The current situation is that:

• The App plumbing does extract the intended log-level, and set it on the databricks logger.

• The App plumbing also installs the custom logging handler on the root logger.

• The root log-level is left as-is. (It defaults to WARNING).

• The attached handler is set to handle anything at DEBUG or higher.

• The application logger (which is typically under databricks.labs.[…]) has its level set:

  • If the app seems to be running within an IDE-based launcher (is_in_debug()): DEBUG
  • Otherwise: INFO

Crucially, even though the databricks logger has been set to DEBUG, the application logger (a child) is set to INFO and DEBUG-level logs will be dropped there, never propagating up to the root or the attached custom handler.