v0.4.0

Tracks alpenglow ag-v0.4.0. Major release adds the Live tab — a
real-time animation surface that tails an actively-written validator
log and presents chain progression, leader-window outcomes, shred
ingress, transaction pressure, and slot lifecycle as continuously
updating visualisations. Plus a runtime truecolor detector + 6×6×6
cube fallback for terminals that misparse 24-bit RGB, and a four-band
fast-finalize verdict ladder calibrated against operator-observed
cluster performance.

Added

• Live tab — real-time tail of an actively-written log. Hidden when
  the log is static (rotated / stale / no size growth observed).
  Press SPACE to start tailing, p to pause the animation,
  h to toggle an in-app glossary that explains every widget
  label and glyph. Composite scene engine with six panes:
  • Shred streams — turbine particle stream + repair/drop/err
    sparklines from ShredFetch / ShredFetchRepair /
    ShredSigverify / RecvWindowInsert metric datapoints.
  • Slot outcomes — fast/slow/skip/FEC lane bars per
    time-slice over a rolling 64-slot window. Skip lane uses
    left-pointing triangle glyphs to read distinctly from the
    slow lane's dots.
  • Chain — cannon-particle visualisation: tip-slot chip and
    cannon at the top, particles fall into a paged 25×5 bucket
    with magic-wipe transition between pages. Left-side tx
    stream surfaces recent BankFrozen.signature_count per
    slot (filters skipped slots and zero-sig blocks). Four
    status chips show cadence / assembly / consensus /
    lifecycle p50/p95 in ms.
  • Block production — recent leader windows as cards with
    per-slot bank time, signatures, broadcast time, shreds, tx
    counts, and outcome icons ([✓] / [~] / […] / [✗] /
    [A]). Headline summarises bank avg / sig max /
    sh max / since last block. Right-aligned timer column
    lands cleanly in the right card slot.
  • Tx pressure — BankFrozen.signature_count thermal area
    chart with cold→hot gradient + dimmed area fill. Header
    surfaces now / avg / peak over the visible window.
  • Decorations — status strip with tail health, recent
    event summary, pause indicator.
• Truecolor detection + 6×6×6 cube fallback (tui::truecolor).
  Routes every Color::Rgb callsite through a runtime helper
  that detects terminal capability at startup. Detection ladder:
  CLI flag → NO_COLOR → COLORTERM=truecolor/24bit →
  TERM_PROGRAM=Apple_Terminal → TERM substring match
  (kitty / alacritty / wezterm / ghostty / iterm / vscode) →
  default true. On the fallback path quantises to the nearest
  of the 216 colours in the ANSI cube so chip backgrounds and
  gradients render correctly on terminals that misparse 24-bit
  SGR sequences (notably macOS Terminal.app).
• --no-truecolor CLI flag to force the 256-colour fallback.
• --force-truecolor CLI flag to skip the detection ladder
  (escape hatch for SSH sessions where COLORTERM was stripped).
  Mutually exclusive with --no-truecolor per clap.
• NO_COLOR env var honoured per the no-color.org convention.
• Replay xtask (cargo xtask replay-log) for offline Live-tab
  development against a captured log.
• Parser support for ProduceWindow, Unable to produce window,
  Triggering parent ready, ParentReady, and the
  shred-pipeline metric datapoints (ShredFetch,
  ShredFetchRepair, ShredSigverify, RecvWindowInsert,
  ShredInsertIsFull, BankingStageCounts).

Changed

• Overview tab fast-finalize headline rebanded to four
  verdicts: perfect (>=98%) (green BOLD), OK (95-98%)
  (green), fine (80-95%) (yellow), degraded (<80%) (red).
  Verdict text shows each band's actual range rather than a
  single lower threshold so the operator reads "I'm in the
  80-95% band" rather than the misleading "above 80%". Text-
  mode runner cutoff aligned with the new FAST_FIN_GOOD_PCT
  (95) to keep CLI and TUI consistent.
• Slots tab gains the LSKIP filter (we voted skip on a slot
  the network ultimately kept canonical — local-skip on a
  canonical slot). Distinct from CSKIP (canonical-skip across
  the cluster).
• Status bar advertises [h] help on the Live tab so the
  glossary toggle is discoverable.

Notes

• Tab key bindings: 1–7 now span all tabs (Live = tab 7,
  hidden in static-log mode).
• Test count: 461 (was 222 at 0.3.3 release). Includes 4 new
  integration tests in crates/abracadabra/tests/truecolor_render.rs
  that prove every Color::Rgb callsite routes through the
  truecolor detector by walking the rendered ratatui buffer
  and asserting zero RGB cells when the fallback is active.