Add deskew overhang mean fill (#223)

* Add flat field correction CLI

New `biahub flat-field` command that applies flat field correction
per FOV and timepoint via submitit/SLURM. Supports selecting specific
channels (others copied as-is) or flat fielding all channels.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* example settings

* style

* test correction

* style

* deskew api

* overhang_fill

* style

* example deskew config update

* correct import

* Fix deskew tests to use renamed deskew_zyx function

The deskew function was renamed to deskew_zyx and the deskew name
was reused for the API wrapper. Update tests to call deskew_zyx directly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Fix pre-commit: black formatting and trailing newlines

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Talon Chandler <talonchandler@gmail.com>

Fix citation (#58)

* moved citation

* formatted with yaml

* keywords must be a list

---------

Co-authored-by: Eduardo Hirata-Miyasaki <edhiratam@gmail.com>

moved citation from wrong location (#57)

moved citation