fix(mobile): keep new threads available during creation

[khoi]

Problem

Opening a newly submitted mobile thread can show “Thread unavailable” while the server is running it. Composer readers can request its bounded snapshot before thread creation commits; the resulting 404 becomes a cached deleted state until the app restarts.

Change

Make reported model, queued count, subagent metadata, and composer queue workflow use selectedThreadDetailRef. This existing selection gate opens detail subscriptions after the server shell arrives or creation delivery succeeds.

Scope and approval

This is a focused fix for the obvious creation race reported by khoi. It applies to the shared iOS and Android thread screen across providers and connection modes. The matching upstream report documents the same ordering and includes a reproduction recording.

Verification

The mounted hook regressions verify zero snapshot requests while creation is pending or rejected, and one request after delivery or server shell arrival. The focused suite passed all 24 tests:

vp test run apps/mobile/src/state/use-thread-detail.test.tsx apps/mobile/src/state/pending-thread-creation.test.ts apps/mobile/src/features/threads/threadContentPresentation.test.ts

Changed-file lint and vp run --filter @supacode/mobile typecheck passed. The simplify pass and both thermos audits found no actionable findings.

Native iOS verification passed on final head 88ea790c3 after integrating the native crash fix from main. An existing conversation opened, and a new task showed its message, entered the starting state, displayed its reply, and reopened without “Thread unavailable”. The earlier Fabric crash occurred on both versions and is resolved by the change in main. Android was not tested. The successful iOS recording and screenshot were captured locally; GitHub attachment upload is unavailable because the collaborative browser is signed out.

Built with GPT-6.1 Sol in Supacode through the Codex harness.

[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	4.9 KiB	4.9 KiB	+40 B (+0.8%)	6.8 KiB	✅
Codex	Thread snapshot wire	3.7 KiB	3.7 KiB	0 B (0.0%)	4.9 KiB	✅
Codex	Live turn WebSocket wire	1.1 KiB	1.2 KiB	+40 B (+3.4%)	2.0 KiB	✅
Codex	Live turn WebSocket decoded	20.4 KiB	20.4 KiB	+41 B (+0.2%)	29.3 KiB	✅
Codex	Live turn messages	1	2	+1 (+100.0%)	8	✅
Claude	Total thread wire	4.9 KiB	4.9 KiB	+41 B (+0.8%)	6.8 KiB	✅
Claude	Thread snapshot wire	3.7 KiB	3.7 KiB	0 B (0.0%)	4.9 KiB	✅
Claude	Live turn WebSocket wire	1.2 KiB	1.2 KiB	+41 B (+3.5%)	2.0 KiB	✅
Claude	Live turn WebSocket decoded	20.7 KiB	20.8 KiB	+41 B (+0.2%)	29.3 KiB	✅
Claude	Live turn messages	1	2	+1 (+100.0%)	8	✅

Baseline: b7d8017 · PR result: 88ea790 · 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: 106.1 KiB
• Claude decoded thread snapshot: 106.4 KiB

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