Add a Keyword casing setting to the code editor

Add a Keyword casing setting to Objo Studio's code editor with three options:

• Canonical (default): use the existing spellings, such as Var, If, and AddHandler.
• Lowercase: use spellings such as var, if, and addhandler.
• Preserve as typed: leave the developer's keyword casing unchanged.

Developers should be able to choose their preferred keyword style while retaining automatic spacing and other editor formatting. The choice should be saved in Studio's preferences and apply to both project source editors and IDE Scripts. Objo is case-insensitive, so the choice does not change how programs behave.