feat: add hasWasmSupport WebAssembly capability check

[antsukanova]

Summary

Adds WebCapabilities.supportsWasm() - a capability check that reports whether the
WebAssembly runtime is available, without throwing when it isn't.

Some environments hard-disable WebAssembly (e.g. Chromium "jitless" mode via
DefaultJavaScriptJitSetting=2), where touching WebAssembly.* throws a
ReferenceError. This lets callers identify the issue early and fail fast.

Changes

• web-capabilities.ts — new supportsWasm() (returns NOT_CAPABLE when the runtime
  is hard-disabled, CAPABLE otherwise).
• isCapableOfBackgroundNoiseRemoval() — now fails fast to NOT_CAPABLE when
  WebAssembly is unavailable, since background noise removal runs as a WASM module.
• isCapableOfVirtualBackground() — now fails fast to NOT_CAPABLE when
  WebAssembly is unavailable, since background video effect runs as a WASM module.
• web-capabilities.spec.ts — tests for supportsWasm and the gated BNR case.
• package.json — add a types entry to the exports map.

Consumer

@webex/web-media-effects will use supportsWasm() to gate noise-reduction loading and
fail fast with a clear error when WASM is unavailable.