[Feature]: Cross context operation access check

### What would you like?

Add a check to ensure an operation is accessed (calling `.get`) only in the context where it's created.

This would disallow the access to an operation in
- its grandparent context
- its sibling context
- etc

There is an exception - `parallel` operation, in which the branches are always used in its grandparent context.

This check currently exists in TypeScript SDK but not implemented in Java SDK

### Possible Implementation

It's straightforward. The context id of the current thread is in thread local object. We can check that with the operation's context id.

### Is this a breaking change?

#### Yes

### Does this require an RFC?

No

### Additional Context

_No response_

Start by finding the existing cross-context access check in the TypeScript SDK, then trace the Java operation `.get` path and the thread-local current context ID. Implement equivalent checks for parent, sibling, and other contexts while preserving the stated `parallel` exception, and verify that valid same-context access still works.

Written by the indexing model from the issue text.