Adds context-sensitive autocompletion for:
- Sound names in s("...") and sound("...") after the opening quote or after whitespace/bracket
- Bank names in bank("...") with quote handling and live filtering
- Scale types in .scale("...") after the colon, inserting colon-form for multi-word names
- Pitch names (C, C#, Db, etc.) for scale keys on explicit completion (Ctrl+Space) before the colon
- Blocks fallback completions in scale context before colon to avoid function list cross-talk
