docs(ck08r3a): freeze portable plan branch ownership proof

[douglasmonsky]

Summary

• Freeze the corrected fail-closed structural proof for the portable SQLite plan exception.
• Bind full EXPLAIN id/parent/detail topology, unique leftmost session ancestry, contiguous session/occurrence/manifestation lookup chain, and the corrected preflight-only test identity.
• Keep production, DDL, schema, publication, provenance, predecessor-rejection, CK-07, and R3A acceptance boundaries unchanged.

Evidence

• Authority commit: 5c5ea3e.
• Authority JSON SHA-256: 46cb417f1f9df623e07e65629645d1d986861d4f45674bce48e4d88b15808400.
• Authority schema SHA-256: 0eca426560751ef8539f35fe2d26e9587c808a5558f6376c36339dbb0308ae35.
• Corrected tests/agent_kernel/evidence/test_service.py SHA-256: bc01c3149101f0fd6c787e23a00c7bd2b2ec21628e8508223b8828df1f13390b.
• SQLite 3.45.1: at most one marker on deep timeline/allowance session branch; first and other shapes marker-free. SQLite 3.53.3: marker-free.
• Foreign lifecycle rows 0/1000/5000: callbacks 21/21/21, seven returned rows each, has_more true, cursor and truth invariants preserved.
• Full preflight: 1403 passed, 1 skipped, 1 warning; full authority: 1390 passed, 1 warning. just vp, just v, just vc, build, dist, GitNexus, diff, and privacy checks passed.
• Anscombe read-only review: PASS, no actionable findings.

Boundaries

• This PR is authority/docs/schema/scope/tests only; the revised support test and 16-path implementation cohort exist only in the isolated non-consuming preflight.
• R3A remains permitted_not_accepted / Conditional Ready. PR CK-08R3A: bound evidence lifecycle queries by session #417 remains held. CK-07 remains blocked_hold with its token unspent and unavailable.
• No live operation, real Codex data, CK-07 launch, token consumption, downstream dispatch, or implementation acceptance is authorized.

After hosted CI and squash merge, perform fresh exact-main verification; only then may the coordinator resume the same R3A worker in a fresh latest-main acceptance worktree.