feat(run_imarisconvert): enhance output folder handling

- Add notes on output folder behavior in docstring.
- Specify that if no output folder is provided, the IMS file will be saved in the input file's directory.
- Clarify output filename construction from input filename.

Author: lguerard

src/imcflibs/imagej/misc.py

@@ -685,6 +685,16 @@ def run_imarisconvert(file_path, pixel_calibration=None, output_folder=""):
         conversion, by default None.
     output_folder : str, optional
         Folder where the newly created IMS file will be saved, by default None.
+
+    Notes
+    -----
+    - If `output_folder` is not provided (or is empty), the converted `.ims`
+        file will be written to the same directory as the input file.
+    - The output filename is constructed by taking the input filename and
+        replacing its extension with `.ims` (for example,
+        `/path/to/image.czi` -> `/path/to/image.ims`).
+    - If the input has an `.ids` extension (part of an ICS-1 pair), the
+        corresponding `.ics` file is used as the source before conversion.
     """
     # in case the given file has the suffix `.ids` (meaning it is part of an
     # ICS-1 `.ics`+`.ids` pair), point ImarisConvert to the `.ics` file instead: