fix(agents): stabilize queue, steer, and timeline ordering

[yoloyash]

Summary

• keep the agent composer visually stable while a turn is active: Enter and the unchanged send button queue the draft instead of exposing a separate delivery-mode toolbar
• render connector-owned queued messages directly above the composer with Edit, Steer, and Delete actions; editing restores text and images to the same composer
• make queued-message promotion the only steering path in protocol v1, removing direct draft-level Steer, Interrupt, and interrupt-queued commands instead of retaining parallel or compatibility paths
• keep durable FIFO queue ownership, command deduplication, and provider transitions in the Host Connector for Codex, Pi, and OMP
• make the Codex adapter emit one authoritative ordered projection for each turn; connector and browser reducers replace that turn atomically instead of deriving order from event arrival timing
• anchor synthetic prompt and steer inputs to their native Codex item boundary, then reconcile late native user echoes without changing logical order or stable client identity

Interaction model

While a provider is working, every ordinary composer submission first becomes a visible queued item. The user can then:

• Edit — remove the item from the connector queue and restore its text/images to the unchanged composer
• Steer — promote the selected queued item into the active native provider turn
• Delete — remove it from the connector queue

Stop remains a separate active-turn control. There is no hidden Command/Ctrl+Enter steering mode; alternate Enter combinations queue as well. When the provider is idle, ordinary composer submissions start a prompt normally. Slash commands continue to normalize into their provider-neutral commands before delivery.

Root cause fixed

The reported order corruption was real and survived reload because the connector runtime snapshot itself was already wrong:

1. Codex can omit live user-item notifications. The adapter synthesized those inputs but appended them after assistant/tool items that had already arrived.
2. The connector and browser then independently upserted each projected row, preserving its first-seen array position. A later corrected projection could update content but could not restore order.

This change gives the Codex provider projection sole ownership of order within a turn. The connector stores that ordered turn block and the browser applies the same block atomically. The exact regression covers user prompt → assistant output → mid-turn steer → assistant output → footer, including the connector snapshot used after reconnect/reload.

Paseo alignment

The interaction and timeline model was audited against getpaseo/paseo@334bf623709d91b9b9d5217fb17acc289ed16622.

Paseo keeps canonical timeline ordering in its daemon and renders queued messages above a stable composer. Its queue-mode setting makes active-run submissions queue first, although its factory setting currently defaults to Interrupt and its queue rows expose Edit and Send Now. OvertChat adopts the stable composer and visible queue-track interaction while keeping the queue in the Host Connector rather than Paseo's app-side session store, so queue state survives browser reconnects and is shared across clients.

Provider behavior

• Codex: queued items promote through native turn/steer; authoritative ordered turn projection
• Pi and OMP: queued items promote through their native RPC steer
• all providers: connector-owned queue/edit/delete, FIFO drain, stable client message IDs, and command journaling

Verification

• npm run typecheck
• npm run lint
• npm run test — 511 passing, 4 opt-in integration tests skipped
• npm run build
• E2E_PORT=4729 npm run test:e2e -w apps/web -- e2e/agent-runtime.spec.ts
• git diff --check

Focused coverage includes provider-neutral queue promotion for Pi/OMP, Codex live projection order, connector snapshot order after a steer race, browser atomic reconciliation, provider acknowledgement after transport rejection, and rejection of delivery commands that bypass the queue. The Playwright flow covers the stable composer, default Enter-to-queue, image-preserving edit, queued Steer, Delete, modifier-key queueing, double-submit prevention, and Stop.

Stack

Stacked on #152. Merge #152 first, merge main into this branch after the parent squash so the diff stays clean, then squash-merge this PR.