Android: new session shows messages in reverse order (assistant reply above user prompt) after stream briefly stalls

[ExRazor]

Bug Description

In a brand-new session, right after I send my first prompt, the streamed response briefly stalls. When the assistant's reply lands, the message order comes out wrong: the assistant's message is rendered above my prompt, even though mine was sent first. The timestamps show it too, my message says "4m ago" while the reply says "1m ago", and the newer reply sits on top of the older prompt.

Steps to Reproduce

1. Open CodeWalk on Android, connected to a self-hosted opencode serve instance (v1, via Cloudflare Tunnel + password auth).
2. Start a new session and send a prompt.
3. Streaming starts, then freezes for a moment.
4. When the response finally appears, it is rendered above the user message instead of below it.

Expected Behavior

Messages stay in chronological order: the user's prompt stays below, and the assistant's reply appears after it.

Actual Behavior

In a fresh session the order is inverted. The reply is placed above the prompt that triggered it, and streaming stalls briefly before the reply lands.

Closing and reopening the app does not fix it either. After force-closing CodeWalk and opening it again, the same session still shows the messages in the wrong order.

Environment

• CodeWalk version: v1.224.0 (latest at time of writing)
• Platform affected: Android (client)
• opencode server: v1 (latest, NOT v2), self-hosted
• Connection: Cloudflare Tunnel + opencode serve password auth, with Tailscale as an alternative connection (I have used both; the issue appeared on both setups)

Additional Notes

This happened on a brand-new session, not a long-lived one, so it looks different from #174 (which was about stalls building up over long sessions). Since that one was fixed recently alongside #175, I suspect the message-list/streaming changes in the latest builds may be involved, but that is just a guess.

I have a screenshot showing the inverted order with both timestamps visible, and I can attach it on GitHub.

[ExRazor]

Screenshot showing the inverted order. Note the timestamps: the assistant's reply says "1m ago" and sits above my prompt which says "4m ago".

[insign]

Additional data point from maintainer testing (same ordering family, image variant):

After sending a message with an attached image, that image message later appears after newer messages, as if it were the most recent one.

Verbatim report (pt-BR): "Eu notei algo assim após anexar uma imagem, a ficou aparecendo depois das novas mensagens, como se fosse a mais recente."

Environment for this observation: CodeWalk v1.229.0 (current main).

This looks related rather than identical: #179 is assistant-reply-above-prompt in a fresh session after a stream stall; this one is an older image message jumping to the bottom. Both point at timeline ordering vs message timestamps / optimistic echo reconciliation. Starting a fix Flow now; will link the commit here.

No root cause claimed yet — investigating ordering, local_user_* echo matching with FilePart, and client-vs-server clock handling.

[insign]

Fix landed on main as 3 commits (no release cut yet, per maintainer request):

• 3279f28 — anchor-based timeline ordering: optimistic local_user_* bubbles keep their causal slot instead of being tail-appended; canonical echoes replace in place; attachment-tolerant echo matching (text + file count + MIME, one-to-one, earliest first); restore heal for pre-fix inverted snapshots. Client-side only, no ADR-023 exception.
• 9008288 — review corrections: heal veto on any preceding prompt, shell ! parity, server-only newest-time, FIFO pairing, removed-echo state change, captionless mime guard.
• d1df53a — review round-2 corrections: exact-branch session/optimistic guards with earliest-claimant one-to-one, restore fail-open (tolerant off pre-hydration), fuzzy file-count guard, FIFO tolerant pairing.
• 5561335 — BEHAVIOR.md documents the new ordering guarantees.

Both reported shapes are covered by regression tests: assistant-above-prompt after a stream stall (incl. clock skew and restart), and image messages jumping to the bottom (rewritten URLs, twin identical sends, cold-start restore).

Please reopen if you still see either shape on a build containing these commits. Residual known limits: fully anonymous transcoded image-only echoes may stay preserved (order still stable); make-check gate has 5 unrelated failures (pre-existing ARB drift + load-flaky timeouts, all green in isolation).

[insign]

@ExRazor can you check again?