Enable Chart.js zoom plugin and drag-zoom on completeness/contamination chart

[Ulthran]

Motivation

• Make the completeness vs contamination scatter plot respond to zoom/pan interactions by reliably registering the Chart.js zoom plugin and enabling drag-zoom when available.

Description

• Update app/templates/isolate_stats.html to look for the zoom plugin across multiple global names, call Chart.register(zoomPlugin) when found, and attach the plugin to the scatter chart via the plugins array while enabling drag zoom.

Testing

• Ran black . which completed successfully and left files unchanged where applicable.
• Ran pytest tests/ which executed and produced 3 passing and 6 failing tests, with failures caused by missing SQLite tables in the test environment (OperationalError: no such table).

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Codex Task

[Copilot]

Pull request overview

This PR enables zoom and pan functionality on the completeness vs contamination scatter plot by integrating the Chart.js zoom plugin. The changes detect the zoom plugin from multiple global variable names, register it with Chart.js, and configure drag-to-zoom along with the existing wheel and pinch zoom options.

Changes:

• Added multi-name fallback detection for the Chart.js zoom plugin to handle different module export patterns
• Enabled drag-to-zoom functionality in addition to existing wheel and pinch zoom options
• Attempted to pass zoom plugin reference to the scatter chart constructor (though this is redundant with global registration)

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[Copilot]

The plugins array should not be used to pass the zoom plugin to the Chart constructor. Chart.js plugins are registered globally via Chart.register() (which is already done on line 97), not through the chart instance's plugins array. The plugins property in the chart constructor is intended for inline plugin definitions or plugin instances with specific configurations, not for registered plugins. Remove lines 303 and 307 as the zoom plugin will be automatically available to all charts after registration.

Suggested change

	const chartPlugins = zoomPlugin ? [zoomPlugin] : [];
	new Chart(context, {
	type: 'scatter',
	data: { datasets },
	plugins: chartPlugins,
	new Chart(context, {
	type: 'scatter',
	data: { datasets },

[Copilot]

The plugin detection order is incorrect. If window.ChartZoom is an object containing a default property with the actual plugin, the current code will return the object itself (line 91) instead of the plugin (window.ChartZoom.default on line 92). The order should check for window.ChartZoom?.default before window.ChartZoom to properly handle module exports where the plugin is in a default property.

Suggested change

	window.ChartZoom ||
	window.ChartZoom?.default ||
	window.ChartZoom?.default ||
	window.ChartZoom ||