The water-spout strip in the footer used to be hard-gated by `!low_motion`,
which meant the typewriter-streaming option silently killed the spout
animation — even with `fancy_animations = true` the strip stayed plain
whitespace. Users testing the typewriter pacing in v0.8.29 reported "where
did the whale go," which is on us: we'd collapsed two concerns
(streaming pacing vs footer animation) onto one flag.
This commit makes the two flags orthogonal:
- `low_motion` governs streaming pacing only (typewriter = one char per
commit tick vs upstream cadence = drain everything queued).
- `fancy_animations` governs whether the spout-strip is rendered at all.
It also wires in a new idea that fell out naturally once the two were
decoupled: instead of driving the wave animation off wall-clock
milliseconds, drive it off a per-turn character-commit counter
(`StreamingState::stream_commit_frame`). The wave then visually moves at
the same cadence as the text:
- Typewriter mode → wave drips at one frame per character.
- Upstream mode → wave surges when V4-pro bursts a warm-cache turn.
- Tool calls and planning pauses → no chars arrive, wave freezes. The
textual `working...` pulse still ticks on wall-clock, so a heartbeat
is always visible.
- New turn (`StreamingState::reset`) → counter zeroes so each turn
opens with a fresh wave shape.
`stream_commit_frame` is a `u64` advanced inside `commit_text` and
`finalize_block_text` by the character count of each committed slice,
so multi-byte UTF-8 (e.g., CJK) advances the wave by one glyph per
character rather than three frames per character — matching the
visual weight of each glyph.
Regression-guarded by five new tests in `crates/tui/src/tui/streaming/mod.rs`:
- `stream_commit_frame_advances_by_character_count_on_commit`
- `stream_commit_frame_counts_unicode_chars_not_bytes`
- `stream_commit_frame_advances_on_finalize`
- `stream_commit_frame_resets_on_reset`
- `stream_commit_frame_freezes_when_no_text_arrives`
Also folds in `cargo fmt` cleanup for two files where prior commits on
this branch landed without re-formatting (`crates/tui/src/tui/ui.rs`
around the new Esc-arm wrapper introduced for the `gg` double-tap, and
the new `fireworks_custom_base_url_preserves_provider_model` test in
`crates/config/src/lib.rs`). No behavior change from those edits.
Settings doc comments in `crates/tui/src/settings.rs` updated to spell
out the new orthogonal semantics so the next maintainer doesn't have
to reverse-engineer it from `render_footer`.
CHANGELOG entry added under a new `[Unreleased]` section.
Hunter Bown
15525751ce