[BUG] Assistant text between tool calls is not rendered in GUI or CLI, though fully persisted in session JSONL (regression of #41814 family, amplified by Fable 5)

Description

When the assistant emits text blocks between tool calls within a single response turn, that text is not rendered anywhere in the UI — neither in the desktop app nor the CLI. The turn's tool calls are collapsed into a single "Ran N commands" summary line; expanding it shows only the command labels. Turn-leading text (before the first tool call) renders normally, and the turn's closing text renders normally. Only interleaved text is lost from display.

The text is fully persisted in the session JSONL — this is purely a rendering defect, not data loss. But the user experiences the assistant as silent through long multi-step sequences, including progress updates and intermediate findings the model emitted specifically to keep them informed.

Steps to reproduce

1. Start a session (desktop app or CLI)
2. Ask for a multi-step task and request narration between steps (e.g. "investigate X, explain what you find between each command")
3. The model emits: text → tool call → text → tool call → text
4. Observe: only the first and last text blocks render; the middle blocks are absent in both surfaces, even after expanding the collapsed tool group ("Ran N commands ▸")

Expected behavior

Interleaved assistant text renders in reading order between (or alongside) the tool calls it annotates.

Actual behavior

Interleaved text is silently dropped from display in both the desktop GUI and the CLI. Ctrl+E / expansion does not reveal it. The JSONL transcript contains it intact.

Environment

• Claude Code v2.1.170 (also observed on 2.1.152)
• macOS (Darwin 25.3.0), desktop app + CLI under tmux
• Model: claude-fable-5 (1M context)

Notes

• Related: #46110, #41907 — closed as duplicates of #41814, fixed in 2.1.101. This is either a regression or a surviving variant: those reports centered on tool calls/old output being hidden; this one is specifically interleaved assistant text being unrecoverable in the display while present in the transcript.
• Fable 5 amplifies the impact: its documented output style emits frequent short updates between tool calls, so sessions on Fable hit this constantly. The model appears silent or terse when it is actually narrating.
• Screenshots of the GUI rendering (collapsed group with missing interleaved text) to follow in a comment.