feat(desktop): private remote Stop control on Known Desktops

[loganj]

Remote Stop 5/5 — mounted controls and executable UI evidence

Mount app-scoped live receiver and explicit agent+Desktop control in Known Desktops. Owner list, bounded result polling, honest unknown/failed feedback and exact-request retry. No inferred location or reachability gate. Mounted interaction test covers confirmed result and retry identity.

Rendered evidence complete: selected / waiting / unconfirmed / confirmed screenshots. The Playwright smoke test drives the mounted control, proves relay ACK is not Stop success, and verifies identical-request retry (one preparation, two byte-identical sends). Native results are mocked at IPC; real two-Desktop lifecycle acceptance remains open.

Latest head dfce9ba3 adds only test support and lane wiring to product head 9ce501a6: smoke spec/registration, mock global-event ACKs, and author-only fanout-family inclusion in the existing Rust CI lane (81/81 passed). The complete 6,255-test frontend suite, TypeScript and Biome pass after these changes. Native/PostgreSQL product code is unchanged; prior full results remain applicable. Remote CI completed successfully at dfce9ba3: current-head run 33916379314. Both relay-backed Desktop integration shards passed. All eight active inventory/Stop PRs have green current-head checks; all remain drafts with no submitted GitHub reviews. This does not replace the outstanding native two-Desktop acceptance.

Draft status and validation

Part of the dependent Multiverse Remote Stop stack on #7333. Not merge-ready or deployed. Ordinary host Stop only; Start/Restart/Move placement and launch-side broker integration remain follow-on work. No native two-Desktop acceptance has been performed.

Aggregate candidate 9ce501a671822cf6c8511a0c3687aad8eb56acb7: full Desktop JS 6,255 passed; full native 3,171 passed, 19 ignored, plus 7 CSP and 3 mixer integration tests; Desktop production build passed (OSS feature variant, not a normal internal release DMG). Workspace/all-target Clippy, Rust/Tauri formatting, Desktop static checks and web checks passed in the aggregate just ci attempt. just ci is incomplete: isolated mobile dependency resolution cannot reach pub.dev; no broad-green claim. Static code review was performed directly; no independent human approval claimed.

Relay/DB validation on exact aggregate product head 9ce501a6 passed all 343 selected PostgreSQL tests, including private storage/query, exact stored request redelivery only to authenticated owner/correct community, and populated migration upgrade. Database discovery guard passes. Two unrelated full-package failures also reproduce at unchanged parent 08fbf9c9: relay mesh echo returns 504 rather than 200, and DB observability source guard finds .fetch_all(pool). No weakening/repair of those checks is included.

Originating conversation: buzz://message?channel=f45d3304-dcf0-44e8-a46d-bcd63b235fbc&id=46556e0bda64b5875ddd6791ccb39797d470c3a7d8512912fd876742eb899d46

[loganj]

Remote Stop — mounted control states

Product source: 9ce501a6 (unchanged in dfce9ba3, which adds test-lane and mock-bridge coverage). Captured with pnpm test:e2e:smoke desktop-stop.spec.ts. These are real mounted UI screenshots with mock native IPC results, not a two-Desktop execution claim. The test verifies delivery is not success, timeout remains unconfirmed, and explicit retry sends identical bytes without signing a second request.

Selected target

An owned agent on a named Desktop, with stale last-heard explicitly independent of Stop availability.

Waiting for native result

Delivery alone does not confirm Stop.

No result

The agent may still be running; the same request remains retryable.

Correlated result

The fixture releases the native result, then retry confirms it without creating a second request.