Create @dotcms/events: one SDK for analytics and experiments #37683

Description

Decision: replace @dotcms/analytics and @dotcms/experiments with a new SDK, @dotcms/events, that does both. One dotEvents object, set up by one init call, runs a single Analytics.js instance for pageviews, conversions, content impressions and content clicks, and runs experiments inside it.

Why one SDK instead of two:

• Experiments depend on analytics: every event carries the visitor's context.experiments, and a pageview on an experiment page waits for the variant decision. Two SDKs meant two instances coordinating that across packages.
• Developers configure one thing: one init, one config, and the same dotEvents import everywhere, instead of two SDKs with their own providers and hooks.
• Traditional (VTL) pages get one script, ca.min.js, instead of @dotcms/analytics's ca.min.js plus the experiments script dotCMS injects today.
• It is greenfield: it sends only what dotCMS accepts today, so there is no custom-event API, and conversions carry a name only.

What it ships:

• @dotcms/events: dotEvents (init, conversion, pageView) and the types its API uses.
• @dotcms/events/markup: experimentMarkup, what a server-rendered page prints so its experiment runs.
• @dotcms/events/react: DotCMSExperiment, which prints that markup in React.
• ca.min.js: the IIFE dotCMS injects into traditional pages. It reads the attributes of ca/html/analytics_head.html and decides experiments from the contentlet wrappers dotCMS prints.

@dotcms/uve, @dotcms/react and the other SDKs do not change.

Acceptance Criteria

• @dotcms/events ships with the SDK release, with its three entries and ca.min.js.
• Headless apps send pageviews, conversions, content impressions and clicks, and run experiments, through @dotcms/events alone.
• Traditional pages run analytics and experiments from ca.min.js alone, once Run @dotcms/events on traditional pages as a new opt-in script, /ext/events/events.min.js #37798 (backend changes that make it the only script) ships.
• @dotcms/analytics and @dotcms/experiments are marked deprecated, with a migration note: window.dotAnalytics becomes window.dotEvents, and track has no replacement, since dotCMS rejects custom events.

Priority

High

Additional Context

• Implementation: feat(sdk-events): add @dotcms/events for pageviews, content events and experiments #37799 (the @dotcms/events draft PR). libs/sdk/events/README.md and CLAUDE.md document the architecture and the decisions behind it.
• Backend: Run @dotcms/events on traditional pages as a new opt-in script, /ext/events/events.min.js #37798 (make ca.min.js the only analytics and experiments script on traditional pages).