Implement +create-float-image, +update-float-image, +get-float-image,
+list-float-images, and +delete-float-image shortcuts wrapping the v3
spreadsheet float_image API. The create reference doc includes the
prerequisite media upload step with the correct parent_type
(sheet_image) to avoid common token mismatch errors.
Implement +set-dropdown, +update-dropdown, +get-dropdown, and
+delete-dropdown shortcuts wrapping the v2 dataValidation API.
This resolves the issue where multipleValue writes silently
became plain text because the prerequisite dropdown configuration
step was not exposed as a CLI command.
Also add lark-sheets-formula.md reference for Lark-specific formula
rules (ARRAYFORMULA, native array functions, date diff, etc.) and
update the dropdown limitation note in SKILL.md to link to the new
+set-dropdown shortcut.
Add 5 new sheet shortcuts for row/column management:
- +add-dimension: append rows/columns at the end
- +insert-dimension: insert rows/columns at a position
- +update-dimension: update visibility and size
- +move-dimension: move rows/columns to a new position
- +delete-dimension: delete rows/columns
Includes unit tests (89-100% coverage) and skill reference docs.
