Add AnyChar key pattern for text-entry modes that matches any Char key.
Add new mode variants to ModeKey: FormulaPanel, CategoryPanel, ViewPanel,
TileSelect, Editing, FormulaEdit, CategoryAdd, ItemAdd, ExportPrompt,
CommandMode, and SearchMode.
Update Keymap::lookup to fall back to AnyChar for Char keys.
Update KeymapSet::get to accept search_mode parameter.
Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/Qwen3.5-35B-A3B-GGUF:Q5_K_M)