Remove legacy grid.js and quick-vis from the main Result panel after the React grid + notebook charts prove themselves

Two legacy DOM/jQuery modules on the main Result panel are kept only as fallbacks behind their new React replacements. Once the replacements are proven in production, remove the old code.

(A) grid.js — ready to remove (functionality fully covered)

The new React grid (src/components/ResultGrid/ResultGrid.tsx + src/scenes/Result/ResultGridAdapter.tsx, migrated in #568) is default-on (useNewGrid: true) and fully covers the old grid's functionality. The old DOM grid (src/js/console/grid.js + grid.d.ts) is still shipped only as a fallback, reachable via ?useNewGrid=0 — param read and persisted in src/providers/LocalStorageProvider/index.tsx:133-160, rendered into <div id="grid" /> in src/scenes/Result/index.tsx:207,451. This escape hatch was for the imminent release; in a future release, after the new grid proves itself in the wild, remove grid.js, grid.d.ts, the useNewGrid toggle + query-param handling, and the <div id="grid"> branch.

(B) quick-vis — a couple of things to settle first

The main Result panel's inline charting is the legacy src/js/console/quick-vis.ts (375 lines, jQuery + SlimSelect + echarts, styles src/styles/_quick-vis.scss, mounted via <div id="quick-vis"> in src/scenes/Result/index.tsx). What it does: charts the active SQL editor result in place (fed the editor's columns/query via the MSG_QUERY_DATASET event bus — src/scenes/Editor/Monaco/index.tsx:1611,1954), with a chart-type picker (bar / line / area), a single X-axis ("Labels") picker, a multi-select Y picker (defaults to all columns but the first), a Draw/Cancel button wired to the global execution manager, and redraw-from-cache when only the chart type changes.

The notebook chart pipeline (src/scenes/Editor/Notebook/CellChart/, echarts) is a superset on charting: types line, area, stepLine, stepArea, bar, stackedBar, scatter, pie, candlestick; type-aware auto-inference (inferChartConfig.ts); X-axis picker, dual (left/right) Y-axis with min/max, partition-by, multi-query overlay, OHLC candlestick (ChartSettingsDrawer.tsx, QueryControls.tsx); zoom; adaptive auto-refresh.

Two things to settle before removing quick-vis:

1. Decide the fate of the Result-panel draw area. Either reuse the notebook chart pipeline inside it (the main editor result keeps an in-place chart, just rebuilt on the notebook charts), or remove the draw area entirely and let charting live only in notebooks. Product decision, not a blocker.
2. Note the query-parameter differences. quick-vis fetches lean — cols= projects to only the chart's columns, plus count:false, timings:false (src/js/console/quick-vis.ts:287) — whereas the notebook draw path fetches the full result (executeSingle, limit: 0,N, no cols — src/hooks/useQueryExecution.ts:42). Worth matching for wide results; minor.

Start by reviewing src/scenes/Result/index.tsx, src/providers/LocalStorageProvider/index.tsx, and the ResultGrid and notebook chart entry points. Confirm the React grid covers the legacy path, then resolve whether the Result-panel draw area should reuse notebook charts or be removed. Done means the chosen product direction is implemented and the legacy grid.js, quick-vis, toggle handling, styles, and mount branches are removed or intentionally retained.