Fixing cursor movements between lines + Improvement editor actions model + adding editor test cases + improving editor tests builders

[FedeLoch]

Fixing cursor movements between lines + Improvement editor actions model + adding editor test cases + improving editor tests builders

In this pr, with @m-demare and @JMLF, we were working on the text editor features. In particular, we modelled the concept of a visual column. As part of this work, we improved the text editor model by representing Editor Actions. Each action now knows about how much to move the cursor.

The editor, on the other hand, is the one who is familiar with the visual and virtual columns.

As part of this work, we improved the editor text test builders by simplifying the contract with these methods. Here is an example of what a new test case looks like:

	self assertFrom: 'self ¶aaaasaasaa<r><t>test' applying: { down . up }
		equals: 'self ¶aaaasaasaa<r><t>test'

	cmd := [:t | t moveLeftCmd: true opt: true ]. "<- A command is a block that knows how to build an editor action"
	
	self assertFrom: 'woArd1 ads¶ word2 word3' applying: { cmd . cmd }
		equals: 'wo¶Ard1 ads word2 word3'

The new model considers the next actions:

• RubMoveDownAction
• RubMoveLeftAction
• RubMoveRightAction
• RubMoveUpAction
• RubMovePageUpAction
• RubMovePageDownAction
• RubMoveEndAction

The feature fix

Before

Before the behavior/experience was as follows:

Screen_Recording_2025-09-26_at_15.07.07.mov

After

Note that the cursor position "remembers" the original column position ( visual position ):

Screen_Recording_2025-09-26_at_15.03.23.mov

We introduce a test case for each possible scenario regarding this feature ( pressing shift and/or cmd while you move the cursor). Also, we added new test cases for those scenarios that weren't contemplated before.

We also removed the deprecated behavior.

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[m-demare]

This was done during the latest sprint, but we didn't have the time to finish. TODOs:

• Invalidate virtualColumn when:
  • Text is inserted
  • Text is deleted
  • There's a mouse click
  • Probably other cases I'm forgetting
• Remove/deprecate methods that've become unnecessary
• Test if all actions still work fine with shift
• Write a PR description