[KeyffMS]

Addresses #117 and #118.

Changes:

• replaces the mixed IRuntimeEnvironment with IRuntimeTargetResolver and IRuntimeFeedback;
• removes the five-raw-delegate RuntimeCoordinator constructor;
• composes named target/feedback adapters in SightAdaptContext;
• limits AutomaticActivationService to target-resolution concerns and RuntimeOverlayActivator to feedback concerns;
• introduces RuntimeOverlayUnavailableException for expected target disappearance during activation;
• diagnoses every top-level activation failure with activation mode and target handle;
• recovers expected Win32/target-availability failures into a safe fault state and preserves automatic target suppression;
• diagnoses and rethrows contract/programming failures after best-effort cleanup;
• prevents cleanup failures from replacing the primary activation failure;
• adds focused tests for native failure, contract failure, cleanup failure and success;
• updates runtime tests and architecture documentation.