[CA-01-S7] Publish causal anchors as witnessed Echo control history

[flyingrobots]

Objective

Make committed causal-anchor admissions first-class witnessed Echo control history. The WAL remains the atomic durability carrier; it must not become a second semantic authority through a recovered registry.

Acceptance criteria

• Recovery exposes an ordered history of committed causal-anchor fact/receipt transitions.
• Every history entry names its causal basis before and after admission.
• Basis-pinned point observations are available without unbounded history reads.
• causal_anchor_by_id() is explicitly a projection over witnessed history.
• Lookup maps are disposable and reconstructible from the ordered history.
• Duplicate/conflicting anchor identities obstruct recovery.
• Uncommitted or malformed anchor evidence is absent or rejected.
• Documentation answers what is authoritative after restart and distinguishes history, WAL, and indexes.
• Deterministic restart witnesses prove index destruction/rebuild preserves observations.

Constraint

Do not duplicate the canonical anchor fact or create a second registry authority. One committed fact/receipt transition is the source; all maps and readings derive from it.

[coderabbitai]

🔗 Related PRs

#358 - feat(core): add admission evidence boundaries [merged]
#379 - feat(core): commit runtime WAL ACK evidence [merged]
#598 - feat(warp-core): add filesystem WAL failure atomicity [merged]
#609 - feat(warp-core): project WAL recovery evidence [merged]
#659 - Admit contract-defined inverse intents from causal history [merged]

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[flyingrobots]

Implemented in commit 8e98008. Causal-anchor recovery now exposes ordered witnessed control history with pre/post bases; point lookups are basis-pinned projections and no persistent anchor map remains. Relevant trusted-host, WAL, external-consumer, doc, format, and Markdown gates pass.