feat: redesign the pwm-tui dashboard (flow strip + dominant overview pane)

[AbdelStark]

Redesigns the pwm-tui front end around a dominant, always-visible overview, with the per-stage detail demoted to a side pane.

Layout

  ◆ ProvableWorldModel  ·  commit and audit a world-model inference
    le-wm V0 predictor  ·  quentinll/lewm-pusht  ·  lerobot/pusht episode  ·  cache …
╭──────────────────────────────────────────────────────────────────────────────────╮
│ ● FETCH ── ● EXPORT ── ● LOAD ── ● INFER ── ● COMMIT ── ● VERIFY ── ● TAMPER     │
│ 769 ms     22.0 s      243 ms    40 ms      0 ms        390 ms      389 ms       │
╰──────────────────────────────────────────────────────────────────────────────────╯
╭ ✦ OVERVIEW ─────────────────────────────────────────────╮╭ ◇ TAMPER ───────────╮
│  ✔ ACCEPT   honest proof verified                       ││ per-stage detail    │
│  ✔ TAMPER CAUGHT  forged matmul op 2 rejected: …        ││ (←/→ to navigate,   │
│                                                         ││  esc to follow)     │
│ checkpoint  68.9 MiB · 303 tensors   int8 params 10,76… ││                     │
│ graph       2,437 ops · 32.40 M MAC  config      dim 1… ││                     │
│ latency     infer 40ms·verify 390ms  witness     689,7… ││                     │
│ freivalds   30 linear projections    float gate  0.282… ││                     │
│ z_next      [0, 7, -40, -11, -10, 3] bundle      43.5 … ││                     │
│ op mix      slice ▰▰▰▰▰▰▰▰ 1,389  concat ▰▰ 373  …      ││                     │
│ commitments weights 3733fc82… export-bound  model 59c… ││                     │
╰─────────────────────────────────────────────────────────╯╰─────────────────────╯
   ACCEPT    ←/→ stage · esc follow · l log · q quit

What changed

• Pipeline flow strip: the seven stages now read horizontally as a flow with state glyphs (done, running spinner, skipped, failed) and per-stage wall times on a second row; the selected stage is underlined. Short labels kick in on narrow widths.
• Dominant overview pane, always on screen, never requires navigating into a stage:
  • Activity zone swaps with the run: per-asset download gauges plus a live throughput sparkline during FETCH; exporter substage dots and the quantize progress bar (plus the last raw log line) during EXPORT; a stage ticker during the proof stages; the ACCEPT / TAMPER CAUGHT (or FAILED) banner once finished.
  • KPI grid (two columns) that fills in live from exporter events before the proof report exists (checkpoint size/tensors, exported int8 params, float gate from calibration, bundle size and its weights root) and sharpens when the report lands (proven params, ops and MACs, infer/verify latency, witness size, Freivalds count, z_next head).
  • Op-mix bars and the commitment table (weights root with its export-bound badge, model, quantization, inputs, output, trace).
• Detail pane stays for advanced per-stage info, navigated with ←/→ (or ↑/↓, j/k), esc returns to following the active stage; the log pane (l) now overlays the detail pane instead of the dashboard. Narrow terminals (< 96 cols) drop the side pane and keep the overview.
• Charm-style look: truecolor palette (lavender/pink/mint/gold on a muted base), rounded padded panels, reversed-video verdict chips, glyph stage states. NO_COLOR still renders cleanly.
• No promotional copy: header and labels are factual (model, checkpoint, dataset, cache path); phrases like "REAL pretrained checkpoint" and "no docker" are gone from the UI.

Mechanics

• app.rs gains a typed Dash struct that absorbs the exporter kv stream (so the dashboard has live numbers before stage 2), a per-tick downloaded-bytes sampler feeding the sparkline, and frozen elapsed time.
• ui.rs is a full rewrite; pipeline.rs blurbs trimmed; keys extended in main.rs. Headless mode, the JSON summary, the pipeline, and the cache are untouched.
• 22 unit tests pass, including TestBackend render assertions for the fetch activity, the post-report dashboard (KPIs, op mix, commitments, verdicts), the narrow-terminal fallback, failure states, and a fluff guard (the rendered frame must not contain "docker" or "REAL"). A dump_frames_for_eyeball test prints full frames under --nocapture for visual review.
• Verified end to end against the warm cache: --headless --offline --json still exits 0 with EXPORT skipped, and the interactive TUI runs and quits cleanly under a pty.