…ng (#702)

Same shape as #549. In pinned mode scrollRows tracks maxScroll, and
maxScroll = inner.height - outer.height. The items useMemo depends on
both scrollRows and outer.height, so a sibling row toggling (ToastRail
appearing, ThinkingRow flipping) shifts outer.height by ±1 → window
moves → a card straddling the live↔spacer boundary flips → inner.height
changes by Δ → setMaxScroll → scrollRows changes → useMemo recomputes →
card flips back. With flash streaming compounding inside the same React
batch, the chain reaches MAX_NESTED_UPDATES and aborts inside ink's
useBoxMetrics (#700).

Quantize the window position to VISIBLE_BUFFER_ROWS buckets. Sub-bucket
scrollRows / outer.height wiggles now map to the same window, so items
is referentially-stable across them and the feedback loop dies on the
first re-render.

- extract computeCardStreamItems as a pure exported function for tests
- new tests/card-stream-items.test.ts asserts live-set stability across
  every sub-bucket scrollRows delta and a range of outer.height values

Closes #700

…he (#989)

Three layered fixes for the streaming-card jitter feedback loop (refs #549 / #700):

- MeasuredCard reports height only on growth for unsettled cards, suppressing Yoga's transient shrink measurements that fed back into virtual-window oscillation. Settled cards still report the exact final height.
- useIncrementalWrap debounces lineCells changes by 120ms via useEffect + useState, holding the previous width during a terminal resize so the incremental wrap stays on its monotonic path until the new width settles.
- Rust render loop adds FrameCache: skip JSON deserialization, scene render, and ratatui diff when consecutive raw frames are byte-identical. Trace scene only changes on card/model/activity updates, so most frames between streaming deltas are duplicates.

…tream (esengine#549)

The "↑ earlier" hint was rendered conditionally on scrollRows > 0, as a
sibling of the measured outer Box. That tied outer.height to scrollRows:
toggling the hint changed outer.height by one row, which changed
maxScroll, which pinned-mode wrote back as scrollRows, which toggled
the hint again. With streaming content compounding inside the same
React batch, the chain reached MAX_NESTED_UPDATES = 50 and aborted with
"Maximum update depth exceeded" inside ink's useBoxMetrics.

Reserve the hint row unconditionally so outer.height is independent of
scrollRows. Trade is one row of permanent reservation; the loop is
gone.

…ng (esengine#702)

Same shape as esengine#549. In pinned mode scrollRows tracks maxScroll, and
maxScroll = inner.height - outer.height. The items useMemo depends on
both scrollRows and outer.height, so a sibling row toggling (ToastRail
appearing, ThinkingRow flipping) shifts outer.height by ±1 → window
moves → a card straddling the live↔spacer boundary flips → inner.height
changes by Δ → setMaxScroll → scrollRows changes → useMemo recomputes →
card flips back. With flash streaming compounding inside the same React
batch, the chain reaches MAX_NESTED_UPDATES and aborts inside ink's
useBoxMetrics (esengine#700).

Quantize the window position to VISIBLE_BUFFER_ROWS buckets. Sub-bucket
scrollRows / outer.height wiggles now map to the same window, so items
is referentially-stable across them and the feedback loop dies on the
first re-render.

- extract computeCardStreamItems as a pure exported function for tests
- new tests/card-stream-items.test.ts asserts live-set stability across
  every sub-bucket scrollRows delta and a range of outer.height values

Closes esengine#700

…he (esengine#989)

Three layered fixes for the streaming-card jitter feedback loop (refs esengine#549 / esengine#700):

- MeasuredCard reports height only on growth for unsettled cards, suppressing Yoga's transient shrink measurements that fed back into virtual-window oscillation. Settled cards still report the exact final height.
- useIncrementalWrap debounces lineCells changes by 120ms via useEffect + useState, holding the previous width during a terminal resize so the incremental wrap stays on its monotonic path until the new width settles.
- Rust render loop adds FrameCache: skip JSON deserialization, scene render, and ratatui diff when consecutive raw frames are byte-identical. Trace scene only changes on card/model/activity updates, so most frames between streaming deltas are duplicates.