[joeblau]

Closes #95
Closes #96

Behavior

Checks run on addDrawing, updateDrawing, moveDrawingPoint, addIndicator, addPane, constructor config, and updateConfig. A rejected call throws chart-ts: and does not change the chart. Render is unchanged.

• Invariant: drawing points have finite index/price and at least minPoints points #95, drawing points. Points must be finite, and a registered drawing needs at least minPoints points, before normalize runs. long-position with [] and signpost with a NaN index throw instead of being stored and breaking every later frame.
• Invariant: indicator and drawing ids are unique (and don't collide with pane ids) #96, unique ids. addIndicator / addDrawing throw chart-ts: duplicate indicator "x" and chart-ts: duplicate drawing "x". An indicator id of main, or one that matches a custom pane, throws chart-ts: indicator id "…" collides with a pane. A pane id of main or of an existing indicator throws the same way.

Tests

1911 tests passed. Coverage is 100% line, branch, and function. bun run typecheck:tsc passed.

Benchmarks

node bench/suite/run.mjs --samples=7 --sizes=100000, Node 24, median ms/op, back to back. These guards are not on the timed paths.

Case	Before	After
100000 setData sorted	0.6708	0.6778
100000 setData shuffled	28.1175	26.9731
100000 DataStore single bar append	0.0005	0.0005
100000 chart appendData streaming	0.1800	0.2081
100000 stored 200 visible redraw	0.7610	0.6976
100000 stored 200 visible live	0.7523	0.7475
100000 stored 5000 visible redraw	8.7469	7.4383
100000 stored 5000 visible live	5.9929	8.3882

Differences are run-to-run noise. Sorted setData moved 0.6708 ms to 0.6778 ms (about 1%).