Fix #472: Emscripten Frontend (#662)

* Fix #472: Add Emscripten/WebAssembly build for browser-based ChaiScript

Port Rob Loach's ChaiScript.js work (https://github.com/RobLoach/ChaiScript.js)
into the main repository as an Emscripten build target. Adds a GitHub Actions
workflow that builds ChaiScript to WebAssembly and publishes artifacts (JS, WASM,
HTML) for embedding in the official ChaiScript.com website. Includes an HTML
interactive playground frontend and a native test validating the eval API surface.

Co-Authored-By: Rob Loach <[email protected]>
Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

* Address review: publish WASM assets as release under wasm-latest tag

Add a publish job to the emscripten workflow that creates a prerelease
tagged wasm-latest with chaiscript.js, chaiscript.wasm, and
chaiscript.html as downloadable assets. Runs only on pushes to the
develop branch. The website repo can fetch these via the public
GitHub Releases API on a daily cron without any cross-repo auth.

Requested by @lefticus in PR #662 review.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

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Co-authored-by: leftibot <[email protected]>
Co-authored-by: Rob Loach <[email protected]>
Co-authored-by: Claude Opus 4.6 (1M context) <[email protected]>

Fix lifetime of objects in ranged for loops

Currently this is going to incur a performance cost, but it's correct.

It may need to be reevaluated.

Closes #392

Merge branch 'develop' of github.com:ChaiScript/ChaiScript into develop

Update release notes

Update release notes for 5.8.5

Increment to 5.8.4

Add support for *& return types

Update to 5.8.2 release notes

Move debug over to windows build

Update release notes and prepare for 5.8.0