Context Manager Task 5 Legacy Fix Report

Status

Updated .pi/agent/extensions/context-manager/src/runtime.ts so syncSnapshotZone() no longer preserves a stored legacy lastZone when lastObservedTokens is missing.
Legacy snapshots without token observations now normalize back to lastZone: "green", which matches the runtime's safe default when pressure cannot be recomputed.
Added regression coverage in .pi/agent/extensions/context-manager/src/runtime.test.ts for both direct restore of a legacy snapshot and the real persisted path of deserializeLatestSnapshot(...) followed by runtime.restore(...).
Left new-schema snapshot behavior unchanged: snapshots that include lastObservedTokens still recompute lastZone against the receiving runtime policy.

cd .pi/agent/extensions/context-manager && npx tsx --test src/runtime.test.ts → 6 passed, 0 failed
cd .pi/agent/extensions/context-manager && npx tsx --test src/runtime.test.ts src/persist.test.ts src/summaries.test.ts → 11 passed, 0 failed
cd .pi/agent/extensions/context-manager && npm test → 35 passed, 0 failed

The fix is narrowly scoped to restore/policy resync behavior for snapshots missing lastObservedTokens.
The public API stays the same.
New-schema snapshots keep the existing recompute behavior.
Legacy snapshots no longer carry a stale red/yellow/compact zone into a runtime that lacks the data needed to validate it.