CompletionSource over the srccfg-vocab.json shape. Word fragment
matched via /[A-Za-z0-9_]{2,}/ at the caret; ranking is
prefix-match-first (shorter prefixes preferred) then substring;
cap 50 candidates, top 8 rendered. Each option carries the kind
('cvar'/'command') as cm6's autocomplete `type` so the popup
shows the appropriate icon.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
