docs: full TypeScript GenAI Observability SDK reference (fix wrong repo link)

[ps48]

What

The TypeScript SDK page (send-data/ai-agents/typescript) was a "Coming Soon" stub that linked to a repo that does not exist: opensearch-project/genai-observability-sdk-js. The SDK is in fact released as @opensearch-project/genai-observability-sdk-ts (source).

This PR rewrites the page to full parity with the Python SDK page.

Changes

• Rewrote typescript.md → typescript.mdx (drops the "Coming Soon" badge), documenting the released API, verified against the SDK source:
  • register() (endpoint/protocol resolution, options, examples incl. SigV4)
  • observe() (three calling styles, Op constants, auto-set attributes, nameFrom, sync/async/generator support)
  • withObserve(), enrich() (param → gen_ai.* attribute mapping)
  • Auto-instrumentation (currently discovers @opentelemetry/instrumentation-openai)
  • score(), evaluate(), Benchmark, OpenSearchTraceRetriever, AWSSigV4OTLPExporter
  • Environment-variable reference and related links
• Fixed the AI Agents landing table (index.md): the JS/TS row now shows the correct package (@opensearch-project/genai-observability-sdk-ts) with status Available, and added a TypeScript SDK reference next-step link.

The sidebar entry and redirects in astro.config.mjs already point to /send-data/ai-agents/typescript/, so no config change is needed.

Notes

• All package/import references use the scoped name @opensearch-project/genai-observability-sdk-ts (the published package, v0.1.1). The unscoped opensearch-genai-observability-sdk-ts on npm is a stale 0.0.1 placeholder and is intentionally not referenced.
• Could not run npm run build locally to render-verify (Astro config fails to load in my local Node environment — reproduces identically on unmodified main, so it's environmental). The new .mdx mirrors the existing, known-good python.mdx structure (same import { Aside } usage).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 55.62%. Comparing base (1cd32c9) to head (1413912).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #439   +/-   ##
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  Coverage   55.62%   55.62%           
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  Files           4        4           
  Lines         169      169           
  Branches       47       48    +1     
=======================================
  Hits           94       94           
  Misses         74       74           
  Partials        1        1           

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