Editor + table stakes: multi-line SQL, naive completion, history, filter, export, themes

Multi-line editor with chroma syntax highlighting; NAIVE completion only (SQL keywords + cached table/column names, prefix match — context-aware completion is the separate #63 spike); persistent searchable query history (absorbs #44) + favorites; `/` fuzzy filter on sources/schemas/tables; CSV/JSON export; OSC-52 clipboard (works over SSH); light+dark themes respecting terminal colors; `?` help overlay generated from the keymap.

**Acceptance:** each feature demoed in the VHS script; history survives restart; completion works with zero configuration.

Start by inspecting the existing CLI entry points, keymap, and VHS demo script; the issue also points to the separate #63 completion spike and history work absorbed from #44. Treat the VHS script as the acceptance checklist: all features should be demoed, history must survive restart, and completion must work with zero configuration.

Written by the indexing model from the issue text.