chore: update todo

TODO.md

@@ -1,14 +0,0 @@
-- [x] add selection + copy support in the rows panel.
-    - should be able to select/highlight an arbitrary rectangle (like vim visual block basically)
-    - should be able to copy selection
-    - copied data should be formatted nicely before inserting into the clipboard (system clipboard)
-        - let's go for a markdown table format and csv format depending on copy action
-    - should be able to copy with row names (`y` keybinding)
-        - `ym` should copy to markdown format
-        - `yc` should copy to csv format
-    - should be able to copy without row names (`Y` keybinding)
-        - `Ym` should copy to markdown format
-        - `Yc` should copy to csv format
-- [x] add ability to update values from the row view
-    - edits remain drafts across pages; Ctrl-Enter / F5 applies the table's changes atomically
-    - explicit NULL, conflict detection, and discard/cancel guards protect unsaved work