feat(testing): let the NoKV live rows route through seeds and pin the SDK wire schema

[wchwawa]

Stacked on #4724 (helper seeds routing). This PR shows both commits until #4724 merges; only the second commit (feat(testing): …) is this change. Kept as a draft until then.

Goal And Delivered Outcome

• Goal/source and gap: the NoKV promotion gate (Promotion gate: LoopX acceptance of experimental/metadata-runtimes NoKV-Lab/NoKV#511, from the maintainer note on feat: add Holt and FDB metadata runtimes NoKV-Lab/NoKV#500) requires LoopX's s0.nokv_live_matrix and s2a.nokv_live_qualification rows to run against a build of NoKV's experimental/metadata-runtimes line, which routes through seeds instead of etcd and moves the wire schema from nokv.workspace.rpc.v9 to v10 under an unchanged 0.11.0 / API 1. Before this change the ladder's env:nokv_legacy gate hard-required NOKV_ETCD + NOKV_ETCD_PREFIX, examples/nokv-shadow-provider/live_e2e.py only built RoutingConfig.etcd, and no report recorded which wire schema the wheel actually spoke, so the gate could not be exercised and a wrong wheel surfaced as nokv_transport_protocol_failed.
• Observable before → after, with the validation row that proves it: the gate now needs the six stack variables plus exactly one routing group, NOKV_SEEDS (comma-separated IP:PORT) or NOKV_ETCD + NOKV_ETCD_PREFIX; neither is nokv_live_env_missing with missing_one_of, both is nokv_routing_env_ambiguous. The live matrix builds the matching RoutingConfig constructor and reports SDK facts (version, API, protocol_schema, routing kind, seed count; never endpoint values). The transport records the helper's nokv_protocol_schema handshake field and types a refused open (NoKVHelperOpenRefusedError.reasonCode); the Stage 2A probe passes that code through and its report carries nokv_protocol_schema; the ladder pins nokv_protocol_schema and nokv_routing_group in bindings and treats a wheel that cannot build the configured routing kind as unverified/nokv_sdk_capability_mismatch on both rows instead of a failed row. Rows real_backend (three runs) and unit.
• Issue/task and intended base: Related to Promotion gate: LoopX acceptance of experimental/metadata-runtimes NoKV-Lab/NoKV#511 and Scoped review invitations and module stewardship #4069 (NoKV-plane evidence scope). Base main, after feat(coordination): accept seed routing and report SDK capability mismatches in the NoKV helper #4724.

Scope And Continuation

• Completed scope and remaining work: complete for the LoopX-side configuration capability the NoKV gate names. The etcd path is unchanged and re-verified. Remaining work is on the NoKV side and in the gate record: the acceptance record on Promotion gate: LoopX acceptance of experimental/metadata-runtimes NoKV-Lab/NoKV#511, the API_VERSION / 0.12.0 decision at promotion, and (later) adoption of the feat(publish): atomic expected workspace incarnation fence on publish_bytes NoKV-Lab/NoKV#508 publish fence.
• Slice boundary / successor: successor = none in LoopX for this gate; the NoKV promotion PR is tracked in Promotion gate: LoopX acceptance of experimental/metadata-runtimes NoKV-Lab/NoKV#511. The boundary is independently testable (three real-backend runs below) and reversible (one commit).

Validation

• Tested revision: d8cc665
• Run state: finished
• Input classes: synthetic | public_fixture | authorized_private_read_only

Check kind	Result	Public-safe evidence / limitation
unit	passed	pytest -q tests/test_nokv_live_e2e_routing.py tests/test_nokv_jsonl_helper.py tests/control_plane/test_shared_goal_authority_e2e.py -k "routing_group or wrong_wheel": 43 passed. New: seeds/etcd constructor selection with endpoint-free facts; ambiguous / missing / capability-mismatch / invalid routing are typed and construct no client; gate missing_one_of, ambiguity, nokv_routing_group bindings, seed and etcd values as privacy tokens, opt-in flag still enforced; Stage 2A probe capability mismatch → unverified, other probe failures still raise. Deterministic ladder projection -m "not stage2c_e2e": 13 passed, 8 skipped (as on main).
real_entrypoint	passed	node --test tests/control_plane_ts/nokv_jsonl_transport.test.ts tests/control_plane_ts/nokv_stage2a_qualification_harness.test.ts: 176 passed, 0 failed. New: the real helper process reports sdkProtocolSchema null for the 0.11.0-shaped fixture and the declared string for a newer-shaped fixture; a seeds config against the release-shaped fixture is NoKVHelperOpenRefusedError with reasonCode nokv_sdk_capability_mismatch and no endpoint in the message.
static	passed	ruff check on changed Python files; python -m mypy (repository configuration, 22 files); tsc --project tsconfig.control-plane.json --noEmit.
real_backend	passed	Regression: this head + NoKV 0.11.0 release wheel + NoKV 0.11.0 owner on the etcd control path, S3-compatible local object store (moto), disposable workbench: s0.nokv_live_matrix + s2a.nokv_live_qualification 2 pass, exit 0; bindings nokv_protocol_schema: null, nokv_routing_group: NOKV_ETCD. Same rows on main da6d797 before the change: 2 pass.
real_backend	passed	Candidate (the NoKV gate): this head + wheel and nokv binary built from NoKV experimental/metadata-runtimes (0c0b7e2ad9 plus NoKV-Lab/NoKV#512 head c105fc999b), Holt-backed single owner reached through NOKV_SEEDS (one seed), same object store class with a fresh bucket/prefix, fresh workbench: 2 pass, exit 0; bindings nokv_protocol_schema: nokv.workspace.rpc.v10, nokv_routing_group: NOKV_SEEDS; Stage 2A report nokv_protocol_schema: nokv.workspace.rpc.v10, 13 checks. Wheel and binary SHA-256 are recorded on NoKV-Lab/NoKV#511.
real_backend	passed	Negative pairing: this head + 0.11.0 release wheel + the seeds environment: both rows unverified/nokv_sdk_capability_mismatch, exit 1 (exit 0 with --allow-unverified), 0 privacy violations. On the intermediate head without the probe/ladder propagation the same pairing was s2a fail/assertion_failed (nokv_transport_protocol_failed), which is the failing-before for the typed path.
regression_parity	passed	Baseline main vs head on the etcd path: identical 2-pass outcome and identical 13 Stage 2A check ids; the nokv_provider matrix rows are byte-for-byte the same set. Privacy: an earlier head reported the routing kind literal (etcd/seeds) in evidence and failed the ladder's own privacy scan because the literal is also a client-config string leaf; reports now carry the variable name (NOKV_ETCD/NOKV_SEEDS).

• Coverage and gaps: the changed paths are the ladder gate/bindings/rows, the live matrix routing selection, the transport handshake capture and the probe's failure classification; each has a deterministic test and was exercised against both real owners. Not run: a wire-level pairing of the 0.11.0 wheel against the v10 owner through static routing (the running owner exposes no placement identifiers to build one; the capability-mismatch pairing covers the LoopX-visible behaviour), multi-seed failover (one seed), FDB runtime, real cloud S3. The candidate wheel still reports 0.11.0 / API 1; only the schema string and the SHA-256 distinguish it, which is what the new bindings record.