Read the default browser from mimeapps.list when launching (#13520)

* Read the default browser from mimeapps.list when launching

omarchy-launch-browser and omarchy-launch-webapp asked xdg-settings for the
default browser on every launch, ~72ms through several POSIX shell scripts.
The new omarchy-cmd-default-browser reads the http handler from the
config-dir mimeapps.list files the way xdg-mime does, desktop-specific list
first, taking the first listed entry whose command is installed, in ~10ms.
With nothing set there it falls back to xdg-settings as before.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Let the first copy of a browser entry decide whether it is installed

A user-local entry whose browser is gone could be rescued by a system copy
of the same ID, which the launchers never read. xdg-mime judges the first
copy found, as the launchers use it, so do the same.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

bin/omarchy-cmd-default-browser

@@ -0,0 +1,58 @@
+#!/bin/bash
+
+# omarchy:summary=Print the desktop entry ID of the default web browser
+# omarchy:hidden=true
+
+# Read the http handler from the config-dir mimeapps.list files the way xdg-mime
+# does, desktop-specific list first, taking the first listed entry that is
+# installed. xdg-settings reaches the same answer through several shell scripts
+# in ~70ms, which every browser and web app launch would otherwise pay.
+IFS=: read -ra data_dirs <<<"${XDG_DATA_HOME:-$HOME/.local/share}:${XDG_DATA_DIRS:-/usr/local/share:/usr/share}"
+IFS=: read -ra config_dirs <<<"${XDG_CONFIG_HOME:-$HOME/.config}:${XDG_CONFIG_DIRS:-/etc/xdg}"
+IFS=: read -ra desktops <<<"${XDG_CURRENT_DESKTOP:-}"
+
+# Installed means the command of the entry the launchers will read, the first
+# one found, still resolves: an entry of Omarchy's own can outlive the browser
+# it launched.
+installed() {
+  local data_dir command
+
+  for data_dir in "${data_dirs[@]}"; do
+    [[ -r $data_dir/applications/$1 ]] || continue
+    command=$(sed -n 's/^Exec=\([^ ]*\).*/\1/p' "$data_dir/applications/$1" | head -1)
+    [[ -n $command ]] && command -v "$command" >/dev/null
+    return
+  done
+
+  return 1
+}
+
+for config_dir in "${config_dirs[@]}"; do
+  for desktop in "${desktops[@]}" ""; do
+    list="$config_dir/${desktop:+${desktop,,}-}mimeapps.list"
+    [[ -f $list ]] || continue
+
+    entries=$(awk '
+      /^\[Default Applications\]/ { section = 1; next }
+      /^\[/ { section = 0 }
+      section && index($0, "x-scheme-handler/http=") == 1 { print substr($0, 23); exit }
+    ' "$list")
+
+    IFS=';' read -ra entries <<<"$entries"
+    for entry in "${entries[@]}"; do
+      if [[ -n $entry ]] && installed "$entry"; then
+        echo "$entry"
+        exit 0
+      fi
+    done
+  done
+done
+
+# Nothing set in a config dir: let xdg-settings search the data dirs and caches.
+# It consults $BROWSER too, which the session points back at omarchy-launch-browser.
+browser=$(env -u BROWSER xdg-settings get default-web-browser 2>/dev/null)
+if [[ -z $browser ]]; then
+  browser=$(xdg-mime query default x-scheme-handler/https 2>/dev/null)
+fi
+
+[[ -n $browser ]] && echo "$browser"