[feat](trx-rs): add build/install script and systemd user services

Provide a one-shot installer and matching systemd *user* units so the
server and client can be built, installed system-wide, and run in the
background without hand-rolled steps.

- script/install.sh: builds all three binaries (trx-server, trx-client,
  trx-configurator) in release mode and installs them to /usr/local/bin
  (configurable via --prefix/--bindir/PREFIX, sudo only when the target
  is not writable). Seeds ~/.config/trx-rs/trx-rs.toml from the example
  without ever overwriting existing config, then installs the user units
  with @BINDIR@ substituted to the real path and runs daemon-reload.
  Flags: --no-sdr, --no-build, --no-systemd, --enable-now.
- script/uninstall.sh: stops/disables the units, removes them and the
  binaries; keeps config unless --purge.
- packaging/systemd/{trx-server,trx-client}.service: user units reading
  the combined config at ~/.config/trx-rs/trx-rs.toml. The client softly
  depends on the server (Wants/After). KillSignal=SIGINT matches how the
  binaries shut down cleanly (SIGTERM is not handled).
- README: new "Install (optional, Linux + systemd)" section.

The web UI assets are embedded in the binary, so an install needs only
the binaries plus a config file — no data directory to ship.

Signed-off-by: Stan Grams <sjg@haxx.space>

script/install.sh

@@ -0,0 +1,156 @@
+#!/usr/bin/env bash
+# SPDX-FileCopyrightText: 2026 Stan Grams <sjg@haxx.space>
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Build trx-rs in release mode and install the binaries system-wide, seed a
+# per-user config, and install systemd *user* services to run the server and
+# client. Idempotent: existing config is never overwritten.
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+
+BINARIES=(trx-server trx-client trx-configurator)
+
+# --- Defaults (override via flags or environment) ---------------------------
+PREFIX="${PREFIX:-/usr/local}"
+BINDIR="${BINDIR:-}"          # derived from PREFIX unless set explicitly
+NO_SDR=0
+DO_BUILD=1
+DO_SYSTEMD=1
+ENABLE_NOW=0
+
+CONFIG_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/trx-rs"
+CONFIG_FILE="$CONFIG_DIR/trx-rs.toml"
+UNIT_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/systemd/user"
+
+usage() {
+    cat <<EOF
+Usage: script/install.sh [options]
+
+Build trx-rs (release) and install it.
+
+Options:
+  --prefix DIR     Install prefix; binaries go to DIR/bin (default: /usr/local)
+  --bindir DIR     Install binaries directly to DIR (overrides --prefix)
+  --no-sdr         Build without SoapySDR support (--no-default-features)
+  --no-build       Skip cargo build; install existing target/release binaries
+  --no-systemd     Do not install the systemd user services
+  --enable-now     Enable and start the user services immediately after install
+  -h, --help       Show this help
+
+Environment:
+  PREFIX, BINDIR   Same as the matching flags.
+
+Installs:
+  binaries  -> ${BINDIR:-$PREFIX/bin} (uses sudo if not writable)
+  config    -> $CONFIG_FILE (from trx-rs.toml.example, only if absent)
+  services  -> $UNIT_DIR/{trx-server,trx-client}.service
+EOF
+}
+
+# --- Parse args -------------------------------------------------------------
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --prefix) PREFIX="$2"; shift 2 ;;
+        --bindir) BINDIR="$2"; shift 2 ;;
+        --no-sdr) NO_SDR=1; shift ;;
+        --no-build) DO_BUILD=0; shift ;;
+        --no-systemd) DO_SYSTEMD=0; shift ;;
+        --enable-now) ENABLE_NOW=1; shift ;;
+        -h|--help) usage; exit 0 ;;
+        *) echo "error: unknown option '$1'" >&2; usage >&2; exit 2 ;;
+    esac
+done
+
+[ -n "$BINDIR" ] || BINDIR="$PREFIX/bin"
+
+log() { printf '\033[1;32m==>\033[0m %s\n' "$*"; }
+warn() { printf '\033[1;33mwarning:\033[0m %s\n' "$*" >&2; }
+
+# Return 0 (true) if writing into $1 needs elevated privileges.
+need_sudo() {
+    local dir="$1"
+    while [ ! -e "$dir" ]; do dir="$(dirname "$dir")"; done
+    [ -w "$dir" ] && return 1 || return 0
+}
+
+# --- Build ------------------------------------------------------------------
+if [ "$DO_BUILD" -eq 1 ]; then
+    build_args=(build --release --manifest-path "$PROJECT_ROOT/Cargo.toml")
+    for b in "${BINARIES[@]}"; do build_args+=(-p "$b"); done
+    if [ "$NO_SDR" -eq 1 ]; then
+        # --no-default-features only affects trx-server; harmless elsewhere.
+        build_args+=(-p trx-server --no-default-features)
+        log "Building (release, no SDR)…"
+    else
+        log "Building (release, with SDR)…"
+    fi
+    cargo "${build_args[@]}"
+fi
+
+# --- Install binaries -------------------------------------------------------
+SUDO=""
+if need_sudo "$BINDIR"; then
+    SUDO="sudo"
+    log "Installing binaries to $BINDIR (using sudo)…"
+else
+    log "Installing binaries to $BINDIR…"
+fi
+
+for b in "${BINARIES[@]}"; do
+    src="$PROJECT_ROOT/target/release/$b"
+    if [ ! -x "$src" ]; then
+        echo "error: $src not found (build failed or --no-build with no prior build?)" >&2
+        exit 1
+    fi
+    $SUDO install -Dm755 "$src" "$BINDIR/$b"
+    log "installed $BINDIR/$b"
+done
+
+# --- Seed per-user config ---------------------------------------------------
+if [ -e "$CONFIG_FILE" ]; then
+    log "Config already present, leaving it untouched: $CONFIG_FILE"
+else
+    mkdir -p "$CONFIG_DIR"
+    install -m600 "$PROJECT_ROOT/trx-rs.toml.example" "$CONFIG_FILE"
+    log "Seeded config from example: $CONFIG_FILE"
+    warn "Edit $CONFIG_FILE for your rig before starting the services."
+fi
+
+# --- systemd user services --------------------------------------------------
+if [ "$DO_SYSTEMD" -eq 1 ]; then
+    mkdir -p "$UNIT_DIR"
+    for unit in trx-server trx-client; do
+        sed "s|@BINDIR@|$BINDIR|g" \
+            "$PROJECT_ROOT/packaging/systemd/$unit.service" \
+            > "$UNIT_DIR/$unit.service"
+        log "installed $UNIT_DIR/$unit.service"
+    done
+
+    if command -v systemctl >/dev/null 2>&1; then
+        systemctl --user daemon-reload || warn "systemctl --user daemon-reload failed"
+        if [ "$ENABLE_NOW" -eq 1 ]; then
+            log "Enabling and starting user services…"
+            systemctl --user enable --now trx-server.service trx-client.service
+            warn "Run 'loginctl enable-linger $USER' to keep services running after logout."
+        else
+            cat <<EOF
+
+Next steps:
+  1. Edit your config:   \$EDITOR $CONFIG_FILE
+  2. Start the services: systemctl --user enable --now trx-server trx-client
+  3. Watch the logs:     journalctl --user -u trx-server -u trx-client -f
+  4. Run after logout:   loginctl enable-linger $USER
+
+Web UI (default): http://127.0.0.1:8080
+EOF
+        fi
+    else
+        warn "systemctl not found; units copied but not reloaded."
+    fi
+fi
+
+log "Done."