feat: support new page triggers - element appeared, element visible and manual

[tyiuhc]

Summary

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📝 Documentation updates detected!

New suggestion: Document new page trigger types for Web Experiment

[macroscopeapp]

Add page triggers for element visibility and appearance and add manual trigger via DefaultWebExperimentClient.activate across experiment-tag package

Introduce element_visible and element_appeared trigger handling with IntersectionObserver and filtered MutationObserver pipelines, add activate(name) to publish a manual trigger, and define discriminated trigger types in types.ts. Debounce for mutation processing changes to 100ms. Tests add observer mocks.

📍Where to Start

Start with trigger evaluation and publishers in SubscriptionManager in subscriptions.ts, then review the new activate method in experiment.ts and payload/types in types.ts.

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📊 Macroscope summarized ca355c0. 5 files reviewed, 4 issues evaluated, 1 issue filtered, 2 comments posted. View details

[macroscopeapp]

Splitting observerKey on : breaks selectors with colons (e.g., input:checked, div:nth-child(2)). Consider splitting at the last colon so the selector stays intact.

Suggested change

	const [selector] = observerKey.split(':');
	const selector = observerKey.slice(0, observerKey.lastIndexOf(':'));

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[macroscopeapp]

URL-change handling isn’t idempotent: stale visibility state/observers persist and event listeners accumulate. Consider a centralized URL-change reset that disconnects IntersectionObservers, clears elementVisibilityState, and guarantees a single reusable element_appeared subscription (or add per-listener unsubscribe in MessageBus).

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[kwliou]

@tyiuhc From a very brief google search, it seems that node.querySelector needs to traverse the whole document anyways so you might as well just use document.querySelector(selector) once instead of looping through these mutation changes.