fix(mobile): keep pending messages in the chat timeline

[juliusmarminge]

Pending mobile sends previously appeared only as a count under the composer, then disappeared from that state before reaching the chat. Render them at the bottom of the timeline with a Pending label and an edit action that restores the message to the composer without losing an existing draft.

Keep the same row identity through delivery, retain acknowledged messages until their timeline echo arrives, and avoid competing scroll and row animations during the handoff. Editing takes ownership before delivery and persists the draft before removing the queued message.

Verification: mobile typecheck and 51 focused tests pass. Verified offline queueing, app reload persistence, edit-to-composer, and reconnect delivery on an iPhone 17e simulator. Targeted lint has warnings but no errors. This changes the React Native client; web, desktop, contracts, and provider adapters are unchanged. Android was not exercised.

Before and after use the same persisted queue, conversation, iOS viewport, and bottom-following state. Before was captured from the actual base implementation.

Before	After

Delivery handoff at normal speed:

Edit a pending message back into the composer

Prepared with GPT-6 in Codex.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR adds a user-facing pending-message timeline and edit workflow, backed by new acknowledgement, draft, and outbox coordination across multiple production components. It also changes existing feed anchoring, insets, and scroll-animation behavior, making the runtime blast radius broader than a straightforward bug fix.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.6 KiB	13.6 KiB	−20 B (−0.1%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.0 KiB	7.0 KiB	−1 B (−0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.6 KiB	6.6 KiB	−19 B (−0.3%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	57.1 KiB	57.1 KiB	0 B (0.0%)	66.4 KiB	✅
Codex	Live turn messages	10	10	0 (0.0%)	21	✅
Claude	Total thread wire	13.6 KiB	13.6 KiB	+40 B (+0.3%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.0 KiB	7.0 KiB	−11 B (−0.2%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.5 KiB	6.6 KiB	+51 B (+0.8%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.8 KiB	57.9 KiB	+88 B (+0.1%)	66.4 KiB	✅
Claude	Live turn messages	8	10	+2 (+25.0%)	21	✅

Baseline: 52b2bf7 · PR result: 37a68a8 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 113.9 KiB
• Claude decoded thread snapshot: 114.6 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.