fix: clone calcParams and figures on indicator override to stop reference aliasing

[NemeZZiZZ]

Problem

Indicator.override assigns calcParams and figures by reference, while every other field goes through merge/clone:

if (isValid(calcParams)) { this.calcParams = calcParams }   // caller's array
...
this.figures = figures ?? this.figures                      // caller's array

Consequences:

1. Shared state across instances. IndicatorImp.extend(template) passes the template's arrays through override, so every instance of a registered indicator shares one calcParams array. Verified by execution: instance.calcParams === template.calcParams (strict reference equality).
2. In-place mutation is invisible to shouldUpdate. _prevIndicator is snapshotted after the mutation target is already shared, so JSON.stringify(prev.calcParams) === JSON.stringify(current.calcParams) and no recalculation happens — the chart keeps showing stale values even though the params changed.

Fix

Assign clones instead of references:

this.calcParams = clone(calcParams)
...
if (isValid(figures)) { this.figures = clone(figures) }

clone returns non-objects (including the styles callback some figures carry) by reference, so function-valued figure properties are preserved.

Verification

Against the real typeChecks.ts on Node: cloned calcParams are value-equal but reference-distinct; mutating the caller's array after override no longer leaks into the instance; figure objects are copied while their styles callbacks are preserved by reference.

Note: a separate, related quirk — merge() copies explicitly-passed undefined (overrideIndicator({ id, visible: undefined }) clears visibility) — is in the shared merge utility and intentionally not bundled here.