fix(mobile): separate expanded thoughts from the next reply#25438

Problem

On Android, expanding a long group of thoughts hard-clips the text immediately above the next assistant reply, without the standard work-log row gap. Reproduced on current main by opening a thread with three long reasoning items and expanding Worked for → Thought (×3).

Change

Wrap reasoning-only detail groups in the existing WorkLogBlock so terminal groups keep their standard spacing. Show the existing bottom gradient while reasoning remains below the nested scroll viewport. Preserve the original scroll-view sizing classes and continuation behavior.

Scope and approval

Fixes https://github.com/pingdotgg/t3code/issues/25283

Triaged bug via the automated issue flow. GitCafe: #25283. Issue sync is enabled; the current GitCafe issue API does not expose the external issue-number mapping, so independent mirror-number confirmation remains pending.

Verification

Draft: native proof is incomplete and this PR is not ready. One independent review approved the code; another found no code bug but requested the missing visual proof. The evidence audit is INSUFFICIENT.

• vp run check:changed: format, lint, both knip passes, and affected typechecks passed both before and after merging current main.
• Real shared-pool Pixel 9, Android API 36, 1080×2424, system text size large, light/dark. Isolated runtime used explicit --home-dir /tmp/issue-25283-home. No live state was used. Metro required EXPO_NO_METRO_LAZY=1 to load the app.
• Observed: long groups gain a bottom fade and terminal spacing; the final line remains reachable without a veil; short groups fit without a fade. Disclosure, theme changes, single reasoning items, mixed and tool-only controls were exercised.
• Unverified: genuine continued-group adjacency (C0/C1), in-place width resize (R0), fit/overflow/reverse transition (R1), and calibrated final-12-unit fade progression (S2). The device lease expired before the auditor could independently recapture. No iOS runtime was available.
• Captures below are baseline 184d915d87 and implementation 261a20e499, before merging current main. The changed file is byte-identical after that merge; integrated final-head recapture is pending.

Evidence index, recordings, synthetic seeds and drivers · Proof matrix · Independent evidence audit

Visible differences: overflowing text gains a bottom gradient; the normal terminal margin moves the preceding bottom-anchored block slightly upward. The auditor also found a 1–2px positional drift between two historical HEAD captures, so exact reproduction is not certified. Diff images omit the system status strip y<60; Diff8 means max-channel delta >8.

Before: expand and scroll · After: scroll, disclosure and theme changes. Detailed steps and capture limitations are in the evidence index and uploaded drivers.

Implementation: Claude Opus 5.5 via Claude Agent; issue lead and evidence: GPT-6.1-sol via Codex.