Fix: Improve code folding functionality and gutter rendering

- Updated folding actions and engine for more consistent behavior.
- Added helper function `is_fold_hidden()` to check fold visibility state.
- Improved gutter renderer to handle collapsible code blocks more reliably.
- Refined tag handling for invisible folds to prevent desync issues.
- Removed code fold Fix related entry in `TODO.md`.

TODO.md

@@ -12,7 +12,10 @@ ___
 
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 ### Fix
+- Fix <Ctrl\>z in multi-insert mode being funky. Insure updates happen on block level.
+       I.E, maybe push updates to queue to insure block undo/redo?
+- Fix multi-insert not acting properly with  -  in word.
+       I.E leader desync on <Ctrl\>left/right
 - Fix on lsp client unload to close files lsp side and unload server endpoint
-- Fix Collapsable code blocks icon desync on new/old lines or text cut/pasted
 
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