refactor(ai): remove unused metadata fields - #61018

…penCode 2.2.6) (#1350)

## Problem

On OpenCode 2.2.6, scheduled Mission wakes no longer start their
passage. Upstream anomalyco/opencode#61018 removed the `metadata` copy
from the LLM messages plugins see in session context hooks. CodeNomad
classified wakes from `metadata.schedule` on that projection, so a 2.2.6
wake looked inconsistent: the drain failed with `schedule-carrier-wake`
and the passage was never admitted.

## Fix

The context projection still carries each native message `id`, and the
stored native message still carries `metadata.schedule`. Wake
classification now resolves user-role context IDs through the existing
bounded native message reader and classifies the authoritative stored
records by type and status, ignoring projected metadata. Resolved
records are reused for the candidate proof, so a wake row is read once.
Classification and recovery reads have separate read and byte budgets,
and exceeding a bound surfaces a coverage error instead of dropping the
wake. Placement, mapping, deterministic identities, source-byte fences,
RPC checks and CAS/high-water behavior are unchanged. The minimum stays
2.2.3.

The canonical authority and bounds contract is in
`dev-docs/MISSIONS_NATIVE_SCHEDULE_TRANSPORT.md`.

Native facts, checked on isolated CLIs:

| CLI | Context message ID | Context `metadata.schedule` | Stored
`metadata.schedule` |
|---|---|---|---|
| 2.2.3 | kept | present | present |
| 2.2.5 | kept | present | present |
| 2.2.6 | kept | absent | present |

## Tests

- Unit coverage for metadata-free and conflicting projections, notices,
compactions, invalid native records, a context of 128 wake entries,
eight recovery reads and independent byte budgets.
- `tests-runtime-contracts` gains a native context/storage check and the
cold scheduled-Mission product check on minimum and latest, and uploads
the fixtures' receipts and failure diagnostics when a step fails. The
schedule fixtures read the actual CLI version instead of a hardcoded
2.2.3, poll for the PID-matching ready registration, and set the `at`
time after activation, just before Play. The cold wait allows 120 s
(leader-lease recovery exceeds 45 s on dev too).
- On 2.2.6, an `origin/dev` snapshot fails the cold product check
(`schedule-carrier-wake`); this branch passes `at` and `in` with the
exact CI command (product step: 102 s on 2.2.3, 208 s on 2.2.6).
- Foundation fixtures pass on 2.2.3 and 2.2.6 (3 CAS applications, cold
recovery, no provider requests); an earlier revision also passed them on
2.2.5. Server Missions suites: 1,406 passed. Server/UI typechecks and
native bundle builds pass. The full runtime-contract sequence passes
locally on 2.2.3 (15 min) and 2.2.6 (23 min 26 s, against the job's
25-minute timeout).

## Known limitation

`experimental.part_rows` (off by default) stores assistant parts in
`session_part`, which CodeNomad's history, search, outline, gallery and
pruning readers do not read. Documented in
`dev-docs/SESSION_HISTORY_QUERIES.md`, not addressed here.