[zhongkechen]

The OpenTelemetry guide still registers plugin instances that the current SDK 3.x APIs reject, recommends Python's unimplemented W3C extractor, and describes outdated sampling behavior. Update the guide and all six handler examples to the supported factories, including Java's public handleRequest override.

Remove the stale experimental/non-production warning: the JavaScript 3.0 release removes the plugin interface's experimental/beta labels, and the Python OTel package metadata declares Production/Stable.

Consolidate repeated deployment templates and trace explanations into shared setup and a view comparison. Correct fallback-root export, sampling differences, log correlation, and failure/replay guidance; document TypeScript's flush budget. The page is about 36% shorter by word count.

Python #865 and #869 are explicitly marked as pending, with the behavior before and after their fixes. This documentation can merge independently because it does not present those changes as released.

Implementation checked against JavaScript b92df515, Python 4625d01b, Java 64339d4f, and shared conformance requirements b0340ba. The two Python fix revisions were 352a137f and 626c1756. Also reviewed the open Python OTel conformance and lifecycle test PRs; this guide makes no new deployed-service qualification claims.

Validation:

• Repository-wide mdformat --check docs/ and codespell docs/ passed; final edited page rechecked.
• Zensical 0.0.40 production build: no issues. All 687 example references resolve. Generated HTML contains the expected tables and expanded snippets; local fragment links checked.
• TypeScript handler and custom-provider examples type-check against core 3.0.0 / OTel 2.0.0.
• Java handler and custom-provider examples compile against SDK/plugin 3.0.0 and OpenTelemetry 1.65.0.
• Python handler registrations and provider example initialize against the checked source (core 3.0.1 / OTel 2.0.0).
• git diff --check passed. No cloud deployment or conformance suite execution.

The browser policy blocked local-file visual preview; generated HTML was inspected programmatically instead.