Add the Perplexity desktop app to Install > AI

Follows the T3 Code / Grok Bot flow: the Install > AI entry runs
omarchy-install-and-launch, so picking it installs the perplexity
package on demand and launches the app when the install finishes.
Remove > AI drops the package along with the app's own config, flags
file, and rpc-server runtime cache, keeping the perplexity-* caches
that belong to Perplexity's other products. Like the Hermes remover,
it sets -u so an unset HOME is a refusal rather than rm -rf paths
rooted at /.

The menu mark is a new U+E90B glyph in the Omarchy icon font, so it
reaches desktops through the next omarchy-settings release.

Co-Authored-By: Fable 5 <noreply@anthropic.com>
Co-Authored-By: Codex XHigh <noreply@openai.com>

test/shell.d/menu-test.sh

@@ -638,5 +638,5 @@ assert(
 JS
 
 font_charset=$(fc-query --format='%{charset}' "$ROOT/default/fonts/omarchy/omarchy.ttf")
-[[ $font_charset == *"e900-e90a"* && $font_charset == *"e90c"* ]] || fail "Omarchy icon font includes every custom menu glyph"
+[[ $font_charset == *"e900-e90c"* ]] || fail "Omarchy icon font includes every custom menu glyph"
 pass "Omarchy icon font includes the official agent marks"