Keep first response below its prompt

[VolkerChristian]

Cause

When reasoning arrived before its authoritative userMessage, raw protocol arrival order put reasoning before the prompt. The local card retained its admission anchor while live, but the compact alias kept only visual identity; after the animated card became the blue authoritative card, it could move below reasoning.

Fix

• Commit an explicit start boundary when an unanchored prompt dispatches.
• Retain the existing admission anchor and ordinal in the compact visual alias.
• Project the local, transitioning, and compact blue card from that same boundary.
• Return requeued recovery prompts to unresolved tail behavior until hydration.
• Keep protocol values, event order, card composition, and existing authorities unchanged.

Regression coverage

Covers reasoning-first and user-first arrival, empty and continued threads, exact client-ID materialization, the accepted transition, compact blue-card reconstruction, pre-hydration retained history, and requeue recovery.

Before the fix, the new deterministic regression reported four ordering failures. After the fix, all checkpoints pass.

Validation

• Focused projection and card tests: 2/2 passed
• Complete suite: 7/7 passed
• Codex review: approve
• Claude review: unavailable because Claude Code returned HTTP 429 session-limit; no verdict was inferred