Ask RTKit directly for the speaker tuning's realtime priority (#12958)

The tuning host loaded module-rt with default arguments, so it asked for
realtime through xdg-desktop-portal. A portal started before rtkit was
installed reports a realtime budget of zero. module-rt applies that as a
hard RLIMIT_RTTIME of 0, RTKit still makes the data thread SCHED_RR, and
the kernel kills the host with SIGKILL as soon as audio plays; systemd
restarts it every two seconds and the speakers stay silent until the next
login.

Set rtportal.enabled = false, as the stock pipewire.conf does. The host is
a user service in the same session as the PipeWire daemon and has no
reason to go through the portal.

The host config is only copied by `omarchy-audio-tuning on`, so a
migration replaces an installed copy that is still Omarchy's own with the
old setting, and restarts the host if it runs. It does not call `on`,
which would overwrite a tuning graph another tool wrote under the same
name.

Co-authored-by: Michael de By <contact@michaeldeby.nl>

test/shell.d/speaker-tuning-rtkit-migration-test.sh

@@ -0,0 +1,56 @@
+#!/bin/bash
+
+set -euo pipefail
+source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
+
+tmp_dir=$(mktemp -d)
+trap 'rm -rf "$tmp_dir"' EXIT
+mkdir -p "$tmp_dir/bin"
+export XDG_CONFIG_HOME="$tmp_dir/config" OMARCHY_PATH="$ROOT" CALL_LOG="$tmp_dir/calls"
+export PATH="$tmp_dir/bin:$PATH"
+
+cat > "$tmp_dir/bin/systemctl" <<'SH'
+#!/bin/bash
+printf '%s\n' "$*" >> "$CALL_LOG"
+SH
+chmod +x "$tmp_dir/bin/systemctl"
+
+migration="$ROOT/migrations/1790114905.sh"
+host_source="$ROOT/default/audio/filter-chain-host.conf"
+host_config="$XDG_CONFIG_HOME/pipewire/omarchy-speaker-tuning.conf"
+mkdir -p "${host_config%/*}"
+
+grep -q 'args = { rtportal.enabled = false }' "$host_source" ||
+  fail "the shipped tuning host asks RTKit directly"
+pass "the shipped tuning host asks RTKit directly"
+
+# The copy an earlier Omarchy installed: the same file with the old setting.
+sed 's/args = { rtportal.enabled = false }/args = { }/' "$host_source" > "$host_config"
+: > "$CALL_LOG"
+bash -euo pipefail "$migration" >/dev/null
+cmp -s "$host_source" "$host_config" || fail "an installed Omarchy host is replaced"
+grep -Fxq -- "--user try-restart omarchy-speaker-tuning.service" "$CALL_LOG" ||
+  fail "a replaced host is restarted if it runs"
+pass "an installed Omarchy host is replaced and restarted"
+
+: > "$CALL_LOG"
+bash -euo pipefail "$migration" >/dev/null
+[[ ! -s $CALL_LOG ]] || fail "the migration is idempotent"
+pass "the migration is idempotent"
+
+# Another tool's host under the same name, as a community calibrator writes it.
+foreign='context.properties = { log.level = 0 }
+context.modules = [
+  { name = libpipewire-module-rt args = { } flags = [ ifexists nofail ] }
+]'
+printf '%s\n' "$foreign" > "$host_config"
+: > "$CALL_LOG"
+bash -euo pipefail "$migration" >/dev/null
+[[ $(cat "$host_config") == "$foreign" && ! -s $CALL_LOG ]] ||
+  fail "a host another tool wrote is left alone"
+pass "a host another tool wrote is left alone"
+
+rm -f "$host_config"
+bash -euo pipefail "$migration" >/dev/null
+[[ ! -e $host_config && ! -s $CALL_LOG ]] || fail "no tuning installed means nothing to do"
+pass "no tuning installed means nothing to do"