V2 P0: Temporal Truth Engine — validity, state-at-time, supersession ranking

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Background

V2 must distinguish what is true now vs historically vs when Cortex learned it.

Problem Statement

Age is conflated with validity; superseded memory can outrank active claims; no state-at-timestamp query.

Proposed Solution

• Temporal statuses: CANDIDATE, VERIFIED, ACTIVE, CHALLENGED, SUPERSEDED, ARCHIVED, QUARANTINED, ERASED
• Fields: valid_from, valid_to, observed_at, invalidated_at, superseded_by
• API: GET /memory/state?entity=…&at=…
• Ranking: active valid > superseded; age alone does not reduce truth
• Reuse existing SUPERSEDES / causal chain in graph/query.py

Acceptance Criteria

• Current-state vs historical-state tests
• Superseded does not silently win current queries
• Temporal metadata available to reliability gate

Depends on

Data foundations

Plan ref

todo temporal-truth — V2 Enhancement 3