Let Dev Updater supervise the backend instead of shipping a script

dev-updater now carries a built-in service implementation, generated from
a template and driven through the identical interface a project-supplied
script uses, so a project whose service is unremarkable no longer writes
one. ai-app's was unremarkable: `ExecStart=$BINARY` and `command="$BINARY"`
with no arguments and no environment. 233 lines of it, and the half that
matters most -- the OpenRC branch, which neither project can exercise from
a systemd machine -- existed twice, so a fix found by testing would have
had two places to land and no way to notice the second.

The field keeps its name; `Managed` takes the command, resolved against
the component's `cwd`.

The one thing the script said that the built-in cannot is kept, in
AGENTS.md rather than lost: Stop on this card takes down the server a
phone reaches through the tunnel, while Dev Updater itself is unaffected
because it uses its own port -- which is exactly what makes that button
easy to press and easy to regret.

NOT SAFE TO PULL BLIND. A managed service is named after the component, so
this one becomes `app-backend` while the installed one still has the name
the script gave it. Uninstall from the backend card *before* taking this
change, then Install after; pulling first orphans a service that stays
enabled and starts at boot with nothing pointing at it.

.dev-updater.ron

@@ -18,9 +18,17 @@ components: [
         name: "backend",
         build: "cargo build --release",
         cwd: "server",
-        // Installs into whichever user-service manager is here, and is how
+        // Dev Updater's own built-in service implementation, generated
-        // ai-server is started, stopped and asked about. See the script.
+        // into its data directory and driven through the same interface a
-        service: "server/service",
+        // project-supplied script would be. ai-app carried a script of its
+        // own until 2026-08-28; it ran `target/release/ai-server` with no
+        // arguments and no environment, which is the generic case exactly,
+        // so it was two copies of one thing and the copy that could not be
+        // tested from here -- the OpenRC branch -- was duplicated with it.
+        //
+        // Resolved against this component's `cwd`, so this is
+        // `server/target/release/ai-server`.
+        service: Managed("target/release/ai-server"),
     ),
     Apk(
         name: "app",

AGENTS.md

@@ -48,10 +48,21 @@ repo is in PLAN.md's "Backend layout" section.
   event model mirror; `ServerConfig.kt` settings + Keystore-sealed token;
   screens in `SessionListScreen/SessionScreen/SpawnScreen/SettingsScreen`.
 - `.dev-updater.ron` — what Dev Updater is asked to do with this checkout:
-  the backend (built in `server/`, installed and controlled through
+  the backend (built in `server/`, run as `service: Managed(...)`) and then
-  `server/service`) and then the APK (built in `app/`), in that order. The
+  the APK (built in `app/`), in that order. The project it serves is the
-  project it serves is the repository, not either half of it, which is why
+  repository, not either half of it, which is why this sits at the root
-  this sits at the root rather than in `app/`.
+  rather than in `app/`.
+  `Managed` means Dev Updater supervises `ai-server` with its own built-in
+  service implementation rather than a script kept here. ai-app had such a
+  script until 2026-08-28 and it was the generic case exactly — no
+  arguments, no environment — so the two projects were maintaining one
+  behaviour twice, including the OpenRC branch neither can test from a
+  systemd machine.
+  Worth knowing before pressing it: **Stop** on the backend card stops the
+  server that a phone reaches through the tunnel, so on that phone it stays
+  down until someone starts it again from Dev Updater. Dev Updater reaches
+  it over its own port and is unaffected, which is what makes the button
+  safe to press and easy to regret.
 - `wg-app-link/` — a **git submodule**, and the half of this backend that
   dev-updater also needed: the pinned CA and leaf (`certs`), QR enrollment
   and the bearer token (`enroll`), wg0 binding and the certificate's SANs

server/service

@@ -1,233 +0,0 @@
-#!/bin/sh
-# Installs and controls ai-server as a user service, for Dev Updater to
-# drive from the phone -- and for you to drive by hand, which is the same
-# thing.
-#
-# Declared as the Server component of this checkout in `.dev-updater.ron`
-# at the repository root, so the card drives it like any other project's.
-# One button is worth knowing about before pressing it: on a phone that
-# reaches ai-server through the tunnel rather than through Dev Updater,
-# Stop leaves this server down until someone starts it again here.
-#
-#   ./service install | uninstall | start | stop | restart | status | logs
-#
-# `status` prints exactly one of `running`, `stopped`, `failed` or
-# `not-installed`
-# and exits 0. Anything else it prints, or any non-zero exit, means it
-# could not tell -- which the card shows as "couldn't check" rather than
-# as a service that is down.
-#
-# Nothing here ever prompts. Dev Updater runs this with stdin closed and no
-# terminal, so a `sudo` password prompt would not fail, it would hang until
-# the timeout with the card stuck mid-action. Anything needing root exits
-# with a message telling you to run it yourself once instead.
-#
-# User services on purpose: a system unit needs root to install, and a
-# build machine's own account is where a dev server belongs. Note that a
-# user service stops at logout unless lingering is enabled
-# (`loginctl enable-linger $USER`), which you want for this one: the phone
-# reaches this server whether or not anyone is logged in at the desk.
-set -eu
-
-SCRIPT_DIR=$(cd "$(dirname "$0")" && pwd)
-NAME=ai-server
-BINARY="$SCRIPT_DIR/target/release/$NAME"
-
-# Where this service's output goes, and the one generation kept behind it.
-#
-# Under $XDG_DATA_HOME rather than the checkout: a log is generated data,
-# it outlives any one build, and the repository is shared with a machine
-# that should not be able to read it. Rotated on start rather than by size
-# or age, so what is kept is exactly "this run and the one before" -- which
-# is the pair worth having after a crash and a restart, and is the reason
-# the file is not simply appended to forever.
-LOG_DIR="${XDG_DATA_HOME:-$HOME/.local/share}/$NAME"
-LOG="$LOG_DIR/$NAME.log"
-LOG_PREVIOUS="$LOG.1"
-
-# Which init system is here, decided by asking rather than by looking for a
-# binary: a machine can carry both, and an OpenRC older than 0.60 has
-# rc-service but no --user at all.
-detect() {
-    if command -v systemctl >/dev/null 2>&1 &&
-        systemctl --user show-environment >/dev/null 2>&1; then
-        echo systemd
-    elif command -v rc-service >/dev/null 2>&1 &&
-        rc-service --user --help >/dev/null 2>&1; then
-        echo openrc
-    else
-        echo none
-    fi
-}
-
-MANAGER=$(detect)
-if [ "$MANAGER" = none ]; then
-    echo "No user-service manager here: this needs systemd with a user bus," >&2
-    echo "or OpenRC 0.60+ (older ones have no --user). Run $NAME by hand." >&2
-    exit 1
-fi
-
-# OpenRC keeps user-service state under XDG_RUNTIME_DIR and refuses without
-# it. Worth saying plainly: from a server started outside a login session
-# it can be unset, and the failure otherwise reads as a broken service
-# rather than a missing variable.
-if [ "$MANAGER" = openrc ] && [ -z "${XDG_RUNTIME_DIR:-}" ]; then
-    echo "XDG_RUNTIME_DIR is unset, and OpenRC stores user-service state in it." >&2
-    echo "Set it at login (elogind or pam_xdg) and try again." >&2
-    exit 1
-fi
-
-SYSTEMD_UNIT="${XDG_CONFIG_HOME:-$HOME/.config}/systemd/user/$NAME.service"
-OPENRC_UNIT="${XDG_CONFIG_HOME:-$HOME/.config}/rc/init.d/$NAME"
-
-installed() {
-    case "$MANAGER" in
-        systemd) [ -f "$SYSTEMD_UNIT" ] ;;
-        openrc) [ -f "$OPENRC_UNIT" ] ;;
-    esac
-}
-
-# Whether the service fell over, as opposed to being stopped on purpose.
-#
-# OpenRC prints `crashed` *and* exits non-zero for this, so the word is
-# read rather than the exit code -- leaning on the code would report
-# "couldn't check", which is a different and less useful thing to say.
-# The `running` check above stays on its exit code, which already worked
-# and does not depend on wording.
-crashed() {
-    case "$MANAGER" in
-        systemd) systemctl --user --quiet is-failed "$NAME" ;;
-        openrc) rc-service --user "$NAME" status 2>/dev/null | grep -qw crashed ;;
-    esac
-}
-
-require_binary() {
-    [ -x "$BINARY" ] && return 0
-    echo "No built server at $BINARY -- build it first." >&2
-    exit 1
-}
-
-do_install() {
-    require_binary
-    mkdir -p "$LOG_DIR"
-    case "$MANAGER" in
-        systemd)
-            mkdir -p "$(dirname "$SYSTEMD_UNIT")"
-            cat > "$SYSTEMD_UNIT" <<UNIT
-[Unit]
-Description=$NAME (installed by $SCRIPT_DIR/service)
-
-[Service]
-ExecStart=$BINARY
-Restart=on-failure
-WorkingDirectory=$SCRIPT_DIR
-# Appended rather than truncated: the unit is not the thing that decides
-# when a log starts over, since the start subcommand rotates. Restarting
-# inside one run (Restart=on-failure) then keeps the whole story rather
-# than erasing the reason. Needs systemd 240+.
-#
-# No backticks in this heredoc: the delimiter is unquoted so that \$LOG
-# expands, which means a backtick would run as command substitution while
-# the unit is being written.
-StandardOutput=append:$LOG
-StandardError=append:$LOG
-
-[Install]
-WantedBy=default.target
-UNIT
-            systemctl --user daemon-reload
-            systemctl --user enable "$NAME" >/dev/null
-            ;;
-        openrc)
-            mkdir -p "$(dirname "$OPENRC_UNIT")"
-            cat > "$OPENRC_UNIT" <<UNIT
-#!/sbin/openrc-run
-name="$NAME"
-description="$NAME (installed by $SCRIPT_DIR/service)"
-command="$BINARY"
-command_background=true
-directory="$SCRIPT_DIR"
-pidfile="\${XDG_RUNTIME_DIR}/$NAME.pid"
-# command_background discards output otherwise, which is why a crash left
-# nothing to read.
-output_log="$LOG"
-error_log="$LOG"
-UNIT
-            chmod +x "$OPENRC_UNIT"
-            rc-update --user add "$NAME" >/dev/null
-            ;;
-    esac
-}
-
-do_uninstall() {
-    installed || return 0
-    case "$MANAGER" in
-        systemd)
-            systemctl --user disable --now "$NAME" >/dev/null 2>&1 || true
-            rm -f "$SYSTEMD_UNIT"
-            systemctl --user daemon-reload
-            ;;
-        openrc)
-            rc-service --user "$NAME" stop >/dev/null 2>&1 || true
-            rc-update --user del "$NAME" >/dev/null 2>&1 || true
-            rm -f "$OPENRC_UNIT"
-            ;;
-    esac
-}
-
-# Keeps the finished run and starts a fresh file for the next one.
-rotate() {
-    mkdir -p "$LOG_DIR"
-    [ -f "$LOG" ] && mv -f "$LOG" "$LOG_PREVIOUS"
-    : > "$LOG"
-}
-
-control() {
-    installed || { echo "$NAME is not installed" >&2; exit 1; }
-    case "$MANAGER" in
-        systemd) systemctl --user "$1" "$NAME" ;;
-        openrc) rc-service --user "$NAME" "$1" ;;
-    esac
-}
-
-case "${1:-}" in
-    install) do_install ;;
-    uninstall) do_uninstall ;;
-    start | restart)
-        # Rotated before the manager is asked, so the file the service
-        # opens is the new one.
-        rotate
-        control "$1"
-        ;;
-    stop) control stop ;;
-    logs)
-        # One path per line, newest first, and nothing else: the caller
-        # wants somewhere to read from, not a formatted report. Printing
-        # nothing at all is the answer for a service with no log yet,
-        # which reads as "not supported here" and costs nobody anything.
-        [ -f "$LOG" ] && echo "$LOG"
-        [ -f "$LOG_PREVIOUS" ] && echo "$LOG_PREVIOUS"
-        exit 0
-        ;;
-    status)
-        if ! installed; then
-            echo not-installed
-        elif case "$MANAGER" in
-            systemd) systemctl --user --quiet is-active "$NAME" ;;
-            openrc) rc-service --user "$NAME" status >/dev/null 2>&1 ;;
-        esac then
-            echo running
-        elif crashed; then
-            # Before `stopped`, because a crashed service satisfies
-            # neither of the other two and would otherwise be reported as
-            # a state somebody chose.
-            echo failed
-        else
-            echo stopped
-        fi
-        ;;
-    *)
-        echo "usage: $0 install|uninstall|start|stop|restart|status|logs" >&2
-        exit 2
-        ;;
-esac