Add the first component and three surfaces

Vega reads a verified Pure module by convention: a table view with a
label column is a list (with optional badge, detail and tone), any other
table is a table, <table>_focus is its focused row, a title view is the
title and other views are fields. lib/vega.aup gives aup apps the tones,
which say what a row means; each surface decides how it looks or sounds.

vega tui draws the screen in a terminal, keeps the focused row in view
and evaluates only the cells on screen; vega cli prints plain lines for
pipes; vega say speaks the screen and each focus change as sentences.
Display width handles Hangul, CJK, emoji, combining marks and controls.

tests/check.py compares the CLI and NUI output with a reference model of
examples/todo.aup line for line, checks 9,600 TUI frames for scrolling,
focus, badge alignment and the number of cells evaluated, drives the
interactive TUI on a pseudo-terminal, and runs every aup example on every
surface.

1 files changed, 15 insertions, 0 deletions

diff --git a/lib/vega.aup b/lib/vega.aup
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index 0000000..8e5b780
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+# Vega for aup apps: `use vega` (AUP_PATH=.../vega/lib).
+#
+# A tone says what a value means, not how it looks. Each surface decides:
+# a terminal may dim muted rows and color danger red, a screen reader may
+# say "danger" before an item. Use them in a `tone` column of a list or
+# table view (docs/design/001-first-component.md).
+fn normal = 0
+fn muted = 1
+fn accent = 2
+fn good = 3
+fn warning = 4
+fn danger = 5
+
+# A tone only when a condition holds: vega.when(task.done, vega.muted).
+fn when(condition, tone) = if condition { tone } else { normal }