allow for users to control method selection

We need a method to allow users to pick the methods that should be included in the IBS.

We can provide an annotation for this:
- `@ibs(includeMCP default true)`
- `@ibsExclude(justMcp default false)`

If you have `@ibs` it means you only expose the annotated methods .

What to take into account: how do we manage dependencies?

The issue names no files, tests, or entry points. Start by locating the Java code that discovers IBS methods and processes annotations, then clarify the intended meanings of @ibs and @ibsExclude and how dependencies should be handled. Done means the selection rules and dependency behavior are agreed and covered by implementation tests.

Written by the indexing model from the issue text.