CppLink path-mapping support

### Description of the feature request:

Currently CppLink does not support [path mapping](https://github.com/bazelbuild/bazel/discussions/22658). This likely isn't as important as CppCompile to most folks, but if your dependency tree that is being transitioned has many binaries that are unaffected by the transition, it's a potentially large cost of duplicate building, duplicate pulling from cache, etc. It's likely that binaries actually affected by the transition won't be dedup'd, but those further down in the dep tree might benefit from this.

### Which category does this issue belong to?

_No response_

### What underlying problem are you trying to solve with this feature?

_No response_

### Which operating system are you running Bazel on?

_No response_

### What is the output of `bazel info release`?

_No response_

### If `bazel info release` returns `development version` or `(@non-git)`, tell us how you built Bazel.

_No response_

### What's the output of `git remote get-url origin; git rev-parse HEAD` ?

```text

```

### Have you found anything relevant by searching the web?

_No response_

### Any other information, logs, or outputs that you want to share?

_No response_

Start by reading the linked Bazel discussion and comparing the requested CppLink behavior with the existing CppCompile path-mapping support mentioned in the issue. Determine the affected linking actions and define tests showing that unaffected binaries avoid duplicate builds or cache downloads while transitioned binaries retain correct behavior.

Written by the indexing model from the issue text.