Update TS SDK doc to 1.9.x

[mjameswh]

What does this PR do?

• Replace various deprecated/non-preferred APIs and idioms by their 1.9.x alternatives, including:
  • WorkflowClient => Client.workflow;
  • Activity's Context.current().info => activityInfo() (same for .sleep(), .heartbeat() and others);
  • WorkflowClientCallsInterceptor => WorkflowClientInterceptor, and no more factory for these;
  • Document and recommend use of Workflow Context Logger and Activity Context Logger, instead of complicated alternatives;
  • Remove references to the sourceMapPath property when passing prebuilt Workflow bundle to a Worker.
  • Fixed all known invalid links to generated TS SDK API docs;
  • Updated Node.js version on TS samples to Node 20;
  • Similarly updated TypeScript to 5.x, and many more dependencies.

Notes to reviewers

1. I tried as much as possible to keep this PR at a "mechanical" level, mostly find-and-replace-kind of things, with rewrites only in places where that was needed. Splitting this into smaller change sets would not make sense IMHO. More "editorial" changes will be covered in subsequent PRs.

2. I also updated dependencies of the Doc repo itself, because that seems the proper thing to do, and because having different versions of Node and TS for the repo vs the samples would make testing samples awkward.

3. This PR is touching several content nodes that are actually not used anymore. I only figured that out after spending time fixing them. Not sure what the policy is regarding unreferenced files.

[flossypurse]

@mjameswh - We just deprecated Assembly. I merged main in - but then realized that you may want to address Roey's comments in code source and use Assembly to propagate first before merging in main, so I reverted to you last commit.

LMK when you have done that, and I can help you merge the Assembly deprecation changes in.