Fix Experience runtime observability core law

[8Dionysus]

Changed surfaces:

• mechanics/experience/legacy/raw/EXPERIENCE_V2_0_LIVING_WORKSPACE_CONTINUITY_RUNTIME.md
• mechanics/experience/parts/continuity-context/tests/test_living_workspace_continuity.py

What changed:

• Added the missing derived runtime observability request step between canonical runtime boundary review and owner landing in the legacy v2.0 Core Law flow.
• Added a continuity-context regression test so the legacy Core Law keeps the aoa-stats observability step aligned with the active runtime flow.

Validation:

• python mechanics/experience/parts/continuity-context/scripts/validate_living_workspace_continuity.py
• python -m pytest -q mechanics/experience/parts/continuity-context/tests/test_living_workspace_continuity.py
• python mechanics/experience/scripts/validate_experience_distillation.py --part continuity-context
• python scripts/mechanics_topology/validate_mechanic_artifact_topology.py --mechanic experience
• python scripts/mechanics_topology/validate_mechanic_landing_logs.py --mechanic experience
• python scripts/mechanics_topology/validate_mechanics_topology.py --mechanic experience
• python scripts/release_gate/release_check.py

Skipped checks:

• None.

Remaining risk:

• Low. The active schema/example/validator already had the observability step; this aligns the preserved raw packet and adds regression coverage.

Decision review:

• No new decision record needed; this does not alter route law or ownership, it repairs an internal contradiction in an already-landed Experience packet.

Next owner route:

• aoa-stats remains the derived observability owner; this PR does not create stats authority or runtime activation.