docs: CHANGELOG.md seeded from published tags, with structure guard

[suchintan]

https://github.com/Skyvern-AI/rustwright-cloud/pull/124

[claude]

Summary

This is a mechanical sync from rustwright-cloud PR #124: adds CHANGELOG.md, four runnable examples, a Node quickstart test, and small docs tweaks. No changes to src/lib.rs, the PyO3/napi FFI boundaries, or the CDP transport — so the security/concurrency/FFI concerns this review usually focuses on don't apply here. Verified the CHANGELOG's claims (CLI, rustwright-mcp, Go/Java/C#/Ruby/PHP bindings) against the actual repo tree — mcp/, go/, java/, csharp/, ruby/, php/ all exist, so nothing is overclaimed. Overall this is safe to merge with a couple of small polish items below.

🔴 Critical Issues (0)

None found.

🟡 Suggestions (2)

• node/package.json: test script changed from node --test test/ to node --test. With no path argument, Node's test runner globs recursively from cwd (the node/ package root) rather than being scoped to test/. Today node/test/ is the only place matching *.test.mjs files live, so behavior is currently equivalent, but this quietly removes the scoping — a future stray *.test.mjs anywhere under node/ (e.g. a generated/build artifact) would now get picked up. Worth a one-line note on why the scope was loosened, or just keep test/ if there's no concrete reason to drop it.
• tests/test_examples.py::test_screenshot_element_example hardcodes an exact pixel width (width == 308) derived from the example's inline CSS (260px + 24px padding × 2). This is brittle if screenshot_element.py's markup ever changes without a matching test update — the height check already tolerates a range for font-rendering variance, but width has no such slack for e.g. scrollbar-width or DPI differences across CI runners. Consider deriving the expected width from the same constants the example uses, or widening the assertion similarly to height.

📝 Minor / Style (2)

• examples/quickstart.js's "is rustwright resolvable" fallback detection matches on the literal error message text "Cannot find module 'rustwright'" (in addition to error.code === 'MODULE_NOT_FOUND'). This is inherently a bit fragile across Node versions/runtimes even though node/test/quickstart.test.mjs pins the current behavior — just flagging it as a known brittleness in example code, not blocking.
• tests/test_changelog.py is a fairly heavyweight 179-line changelog-format validator (full semver parsing, strict-descending-order checks, category/bullet structure) for what's fundamentally a docs-formatting convention. Not wrong, just worth confirming the team wants to maintain this level of enforcement going forward given CONTRIBUTING.md now requires an [Unreleased] bullet per user-facing PR.