tui: surface the operator's messages as a typewriter monolog over the rain

[edwin-zvs]

The operator surfaces genuinely useful lines — e.g. "'run using zarvis' is waiting at the folder trust prompt — press Enter/Yes or exit" — but they only landed in the daemon-owned orchestrator panel, which is collapsed by default. Unless the user opens it, they never see the message.

Design (per discussion)

The operator now surfaces two ways, and it chooses by which event it emits — no new protocol needed:

• Findings to act on / keep → an Operator widget (UiPanel, the existing path that renders in the matrix area). Persistent.
• Monolog / "what I just did" → a typewriter line over the matrix rain. When the orchestrator finishes a turn with substantive text, the rain body briefly becomes a monochrome terminal: the line types out, holds, fades, and the rain resumes. Ambient, visible without opening anything, self-dismissing.

┌─ operator · watching ─────────────────────────┐
│ operator ▸                                     │
│ 'run using zarvis' is waiting at the folder    │
│ trust prompt — press Enter/Yes or exit.▌       │
│  · · (types out, holds, fades → rain resumes)  │
└────────────────────────────────────────────────┘

Why TUI-only (no protocol change)

Assistant Message events are emitted per-delta (streaming fragments). Rather than add a SessionEvent variant, the TUI consolidates the orchestrator's deltas across a turn into one finalized string at turn end (AgentStatus active=false), drops the internal noted/empty no-op token, and plays it once — exactly the "emit once + typewriter" behavior. Message (stream) vs UiPanel (widget) already distinguishes monolog from finding.

Changes

• app.rs: OperatorMonolog state + operator_utterance accumulator; capture in on_notification (accumulate the orchestrator's Assistant text, finalize on turn end); operator_monolog_text() filter.
• ui.rs: render_operator_monolog() — typewriter (type → hold → fade → self-clear), hooked into render_matrix_rain; widgets still render on top so an open widget isn't hidden; only shows while the rain is visible; rides the existing animation tick.
• agent.rs: orchestrator system prompt explains its short text shows as a fading monolog and to use a widget for anything persistent/actionable.

Tests

• operator_monolog_text filter (drops noted/empty, keeps real lines).
• TestBackend render test: draws the operator ▸ prompt + revealed text mid-cycle, returns showing=true; after the full cycle returns false and clears the state.
• 251 cli tests + adapter tests pass; full build clean. Spec 0023 added.

Verification note

Logic + rendering are covered by tests, but the animation is best seen live — the TUI picks up the new agent binary on restart, and the operator picks up the new prompt on /agents restart. Then any operator finding (or e.g. a session sitting at a trust prompt) types out over the rain.