feat: view values of the expression under cursor

[QuadnucYard]

New features:

• Added a command to open a temporary file (like the AST view) to inspect the value under the cursor.
• Added a command link to the hover tooltip to quickly open the value view. (problem: this link can be trimmed if the values are too long)

Some problems:

• The entry file does not follow the active one. Without being pinned, the values are not traced, and thus no value is displayed.
• The number of displayed values is hard-limited by typst tracking, but we do not know if values are truncated.

[QuadnucYard]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a new feature to view the full value of an expression under the cursor. The implementation looks good overall, with a new command and a custom view in VSCode. I've identified a few areas for improvement:

• A bug in associated_path that prevents correct context resolution for the ShowFullValue query, which you've also noted as a problem. I've suggested a fix.
• A very large SIZE_LIMIT constant that could cause performance issues. I've recommended reducing it.
• The VSCode extension sends requests on every keystroke, which can be inefficient. I've suggested debouncing these requests to improve performance.
  With these changes, the feature should be more robust and performant.