Separation of santitizer config to align with current repos

[FScholPer]

What

1. Move from a combined sanitizer-first model to separate configs (address, leak, undefined-behavior, thread).
2. Align policy feature names to toolchain feature names (no policy-specific naming layer).
3. Remove sanitizer-specific extra link runtime flags unless we explicitly document why they are needed.
4. Switch compatibility constraints to per-sanitizer granularity (instead of broad combined-mode constraints).
5. Update docs/examples to reflect per-sanitizer usage as the primary workflow, plus migration notes for compatibility aliases if we keep them.

Acceptance Criteria (DoD)

All steps are done

How

No response