[quickbeard]

Summary

Reworks the session screen into a scrollback-style flow layout: the codev logo + tip sit at the top-left as the transcript's first entry, the prompt rides directly below the last message (or below the banner when the session is empty), and it only reaches the bottom of the screen once the conversation fills it — instead of a centered banner with a bottom-anchored input and a void between them.

• packages/tui/src/routes/session/index.tsx: the banner (Logo + home_bottom tips slot) moves inside the transcript scrollbox as its first entry for root sessions (subagent sessions keep a plain 1-row pad), so it stays above short conversations and scrolls away with history. The scrollbox holds its flex-derived height regardless of content, so its maxHeight is clamped to the content height via a transcriptHeight signal; an unconditional trailing flexGrow spacer absorbs the leftover space below the prompt. Once content overflows, the clamp exceeds the available space and the existing sticky-scroll behavior takes over (prompt effectively bottom-anchored, transcript pinned to the latest output).
• The clamp is measured in the renderer root's layout-changed handler by reading the freshly computed height off the scrollbox content's yoga node, then re-running calculateLayout so the clamp lands in the same frame. (scroll.scrollHeight is a frame stale at that point; painting with a stale clamp shifted the transcript up and back down each streamed line — visible flicker whenever the transcript was shorter than the screen.)
• packages/plugin/src/tui.ts: home_bottom slot props widened from {} to { placement?: "center" | "start" }. The slot is shared with the still-reachable home route, so alignment is opt-in; no prop keeps the centered layout.
• feature-plugins/home/tips.tsx / feature-plugins/system/which-key.tsx: both home_bottom contributors honor placement="start" (left-align; tips drop their paddingTop 3).
• DIVERGENCES.md: updated the session route row and added rows for the three newly-diverged files.

Verification

Drove the real TUI under tmux (120×35/45 and 100×28) through the full lifecycle:

• Empty session: logo top-left, tip beneath, input directly below, empty space at the bottom.
• After a short exchange: banner still visible at the top, input sitting directly under the assistant's reply.
• Streaming stability: sampled 400 rapid capture-pane frames during a multi-stanza generation — the banner row never moved (12 shifted/blank frames before the same-frame clamp fix).
• After a long response: input pinned to the bottom, transcript sticky-scrolled to the latest output; paging up reaches the banner at the top of the scrollback.
• Reopening the session with -c: full transcript renders scrolled to the bottom with the input at the bottom.
• bun turbo typecheck passes across all 31 packages (pre-push hook).
• The home route path is untouched (no placement prop → centered, upstream spacing).
• test/app-lifecycle.test.tsx epilogue test fails identically on clean main (known flake), unrelated to this change.

🤖 Generated with Claude Code