fix(tui): overlays as absolute popups, no painter ghosting

[Exelord]

Summary

You said the TUI was "all broken." It actually mounted and ran, but two
real rendering bugs made it look like trash:

1. Overlays weren't overlays. Help / TaskDetail / AutoExit
   rendered as the last flex child of the column root, not as modal
   popups — so they appeared below the StatusBar and the underlying
   view's bottom cells bled through. That's why the "Closing in 3s"
   text looked corrupted as qrquitsnimmediately.y open. — the
   overlay's text was painted over the unchanged StatusBar hint.
2. OpenTUI's painter ghosts on shrink. Multi-<text> rows (<text> "foo"/> <text "bar"/>) leave stale cells when the right-hand text
   shrinks. So "1/1 25% parallel" → "0/1 25% parallel" produced
   125% paralel artifacts.

Fixes

Overlays now actually overlay

Studied Turbo's crates/turborepo-ui/src/tui/popup.rs for the
pattern: compute a centered Rect, render Clear + popup widget.
OpenTUI equivalent: position="absolute" + explicit top/left/width/height

• opaque backgroundColor.

• App.tsx root gains position="relative" so absolute children
  anchor to it.
• Help, TaskDetail, AutoExit all use position="absolute",
  centered on screen, with fixed (Help / AutoExit) or
  bounded-flexible (TaskDetail) dimensions.

No more painter ghosting

Header, StatusBar, ProgressBar, and each StatsPanel row are
now a single <text> element pre-padded to the full width. Every
cell repaints every frame; nothing left to ghost.

Layout: Overview no longer collapses the task list

TaskList + StatsPanel were both children of a column with no height
hint, so yoga shrank both proportionally and TaskList showed one row.
Gave StatsPanel a fixed footer height (6); TaskList takes the
remainder.

Loading state pre-runStart

Before runStart fires, body now shows "Waiting for tasks…" instead
of empty bordered "Tasks" / "Log" frames. Header shows run … ellipsis
instead of run --------.

Visual check (PTY 140×40)

After the run completes, the final frame now reads:

 vx 0.0.0  run X2AWP45F  tasks build  pkgs 1  ✓1  ▶0  ⏳0  parallel 0%  local cache only
┌─Tasks──────────────┐┌─Log─────────────────────────────────────┐
│✓ a#build 317ms     ││$ echo build-a && sleep 0.3              │
│                    ││build-a                                  │
└────────────────────┘│                                         │
┌─Stats──────────────┐│                                         │
│ throughput   0/s   ││         ┌─Run complete─────────────┐    │
│ parallel %   0%    ││         │  Closing in 3s…          │    │
│ remote ops   0/s   ││         │  Press any key to stay…  │    │
└────────────────────┘│         │  q quits immediately.    │    │
                      │         └──────────────────────────┘    │
                      └─────────────────────────────────────────┘
 ████████████████████████████████████████  1/1  100% parallel
 [1] Overview  j/k select · / filter · ? help · 1-5 switch · q quit

Test plan

• bun src/bin.ts run format clean
• bun src/bin.ts run lint 0/0
• bun src/bin.ts run test — 506/506 pass
• Manual PTY render verified (above)

Caveat

The user's "the tui is trash" framing also suggests possible scope
concerns — Turbo's TUI ships only a task list + log + search +
help popup (no 5 views, sparklines, critical-path, etc). If you want
me to reduce scope toward that single-screen pattern, I can do that
in a follow-up — say the word.

https://claude.ai/code/session_016HXj6HW6bxSn8EYuKcxTD9

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Generated by Claude Code