fix(runtime-host): classify archived Skill queries - #5149

The design is right and the Host-side fix is the authoritative one. skill.catalog.invocable.query was the only session-targeted operation that collapsed an archived Session into internal_failure — AgentGraphCoordinator#assertRootSupervisor throws session_archived (packages/runtime/src/stream-graph-coordinator.ts:1331) and repositoryFailure had no case for it; the new header check mirrors plan-coordinator.ts:280-296. I reproduced #4430 on the base commit and all three new tests go red there.

Two gaps before merge.

P2 — not_found still collapses to internal_failure on the same resolver (reachability ②)

packages/runtime-host/src/server/execution-composition.ts:716 reads the header before the new archived check. A removed Session makes readHeaderSnapshot throw SessionNotFoundError, which repositoryFailure (skill-catalog-coordinator.ts:279-290) turns into internal_failure — #4430 again, sibling condition. session.remove is supported (protocol/operations.ts:327): a renderer holds a sessionId, another window removes the Session, composer-mentions.tsx refreshes on the sessions event and queries a Session that is gone. plan-coordinator.ts:284-295 handles both in one place; splitting them costs a second compatibility-epoch bump later.

Fix: add 'not_found' to INVOCABLE_QUERY_ERRORS (protocol/skill-catalog.ts:54) and wrap the header read:

let header;
try {
  header = await stores.sessionStore.readHeaderSnapshot(sessionId);
} catch (error) {
  if (isSessionNotFoundError(error)) {
    throw new SkillCatalogInvocableContextError('not_found', 'Session does not exist');
  }
  throw error;
}

isSessionNotFoundError is already imported at execution-composition.ts:117; the error code widens to 'session_archived' | 'not_found'.

P2 — the desktop projection has no observable effect (reachability ①)

apps/desktop/src/main/runtime-host-skills-ipc-main.ts:127-139 catches session_archived and returns []. Its only consumer, composer-mentions.tsx:175, already produces the same state on rejection (:194-200): { loading: false, settled: 'empty', skills: EMPTY_SKILLS }. A session_archived rejection is also not an isReconnectableReadFailure (apps/desktop/src/main/ipc-reconnect-policy.ts:85-94), so no reconnect or retry either — both paths give the same empty / menu.

So 14 production lines, the new @maka/runtime-host/client main-process import and 60 test lines assert an unobservable difference. Name the observable difference in the body, or drop the desktop change and keep the PR to the Host contract plus the epoch bump; #4431 already gates the renderer.

P3 — PR body states the wrong epoch

The body says 139 → 140; the diff moves 141 → 142 (packages/runtime-host/src/protocol/index.ts:104). Stale from a rebase, and peers key on the epoch number.

Verification I ran

npm ci + npm run build at the PR head: runtime-host execution-composition.test.js + skill-catalog-protocol.test.js 40 pass, apps/desktop runtime-host-skills-ipc-main.test.js 4 pass; with the five files reverted to origin/main, the three new tests go red (internal_failure on the archived case) while preserves non-archival invocable Skill failures still passes.

let header;
try {
  header = await stores.sessionStore.readHeaderSnapshot(sessionId);
} catch (error) {
  if (isSessionNotFoundError(error)) {
    throw new SkillCatalogInvocableContextError('not_found', 'Session does not exist');
  }
  throw error;
}

All five points from the previous round are addressed, and the result is smaller than what I asked for: the desktop projection is gone, the lifecycle mapping lives next to the resolver that raises it, and repositoryFailure stays generic for the other three catalog operations. not_found and session_archived land in the same wire union under one epoch bump, so there is no second compatibility break later.

Nothing new at P0–P2. One P3 left inline on the archived pre-check.

Verification I ran

Built @maka/runtime-host at head: execution-composition.test.js + skill-catalog-protocol.test.js 43 pass. Ablations:

• Reverting the four production files to origin/main: all four new composition tests and the protocol decode case go red (5 failures).
• Keeping the header pre-checks but deleting only the catch around runWithSessionBindingPreview (execution-composition.ts:735-749): the two race tests go red, the two pre-check tests stay green. The race coverage is real, not incidental.
• Deleting only the header.isArchived pre-check (:725-727): all four stay green — that is the P3 below.

I did not run the desktop suite; apps/desktop is now byte-identical to main.