iris: load application-owned fonts

app/build-icon-font.sh

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+# Rebuilds app/assets/fonts/nerd_icons.ttf.
+#
+# ai-app draws its icons as glyphs in a Nerd Fonts subset it ships, rather
+# than as ordinary Unicode out of whatever the platform resolved. Unicode's
+# own geometric shapes are what this replaced: `tool.rs` set its disclosure
+# mark with U+25B8/25BE/25B4, and once iris stopped bundling fonts
+# (2026-09-07) Iris's phone drew an empty box for them and this VM drew a
+# dot. UI_RULES: "don't rely on characters the platform might not have --
+# ship the glyph or the asset rather than hoping."
+#
+# The whole symbols font is 3 MB for the handful below, so what is
+# committed is a subset. Add a codepoint to GLYPHS *and* to
+# `app/src/ui/icon.rs` (the two lists have to agree -- a codepoint in
+# the Rust that this script did not subset is a glyph that silently isn't
+# there), then run this and commit the result.
+#
+# Needs python3 and network access; fontTools is fetched into a temporary
+# venv, so nothing has to be installed on the machine.
+#
+# The Mono face makes icon metrics stable; the Material Design family keeps
+# their meanings conventional.
+set -euo pipefail
+
+GLYPHS=(
+    U+F035D  # md-menu_down -- a card that is open
+    U+F035F  # md-menu_right -- a card that opens
+    U+F0360  # md-menu_up -- collapse this group again
+)
+
+url=https://github.com/ryanoasis/nerd-fonts/releases/latest/download/NerdFontsSymbolsOnly.zip
+here="$(cd "$(dirname "$0")" && pwd)"
+out="$here/assets/fonts/nerd_icons.ttf"
+work="$(mktemp -d)"
+trap 'rm -rf "$work"' EXIT
+
+echo "Fetching $url"
+curl -fsSL -o "$work/nf.zip" "$url"
+python3 -c 'import sys,zipfile; zipfile.ZipFile(sys.argv[1]).extractall(sys.argv[2])' "$work/nf.zip" "$work"
+
+python3 -m venv "$work/venv"
+"$work/venv/bin/pip" -q install fonttools
+
+unicodes="$(IFS=,; echo "${GLYPHS[*]}")"
+mkdir -p "$(dirname "$out")"
+# The Mono face, where every glyph is one em wide and one em tall, so two
+# icons at the same font size are the same size without either being given
+# one, which makes an icon's box predictable beside a line of text.
+"$work/venv/bin/pyftsubset" "$work/SymbolsNerdFontMono-Regular.ttf" \
+    --unicodes="$unicodes" \
+    --layout-features= \
+    --drop-tables+=DSIG \
+    --output-file="$out"
+cp "$work/LICENSE" "$here/assets/fonts/NERD_FONTS_LICENSE.txt"
+
+echo "Wrote $out ($(stat -c %s "$out") bytes) with ${#GLYPHS[@]} glyphs"