romm: make the library paths follow ROMM_BASE_PATH

Upstream derives everything from one setting:

  ROMM_BASE_PATH = _get_env("ROMM_BASE_PATH", "/romm")
  LIBRARY_BASE_PATH = f"{ROMM_BASE_PATH}/library"

There is no separate library setting; config.yml's roms_folder is only
a folder name inside the library. So ROMM_BASE_PATH in /opt/romm/.env
is the single lever, and everything that names a path has to follow it.

Two places did not. The watcher unit had /var/lib/romm/library written
into ExecStart, so a moved library was still watched at the default and
rescans never fired. It now uses ${ROMM_BASE_PATH}/library, which
systemd expands from the EnvironmentFile the unit already loads.

The Angie alias was derived from the env file, but only while the
install or an update ran. Editing ROMM_BASE_PATH afterwards left the
internal /library/ location pointing at the old path, and since the
backend serves content through X-Accel-Redirect, every download and
every play returned 404 while scanning and metadata kept working.
Re-sync it from an ExecStartPre on angie, so a restart is enough.

Update installs both for existing containers and rewrites the watcher
unit in place.

Reported in #17263. The suggested fix there was to template the alias,
which the scripts already did; the gap was that nothing re-applied it.

ct/romm.sh

@@ -191,11 +191,30 @@ EOF
         sed -i -e "s|alias .*/library/;|alias ${ROMM_BASE}/library/;|" \
           -e "s|alias .*/cache/;|alias ${ROMM_BASE}/cache/;|" /etc/angie/http.d/romm.conf
       fi
+      cat <<'SYNCEOF' >/usr/local/bin/romm-sync-angie-paths
+#!/usr/bin/env bash
+base="$(grep -m1 '^ROMM_BASE_PATH=' /opt/romm/.env 2>/dev/null | cut -d= -f2)"
+base="${base:-/var/lib/romm}"
+[[ -f /etc/angie/http.d/romm.conf ]] || exit 0
+sed -i -e "s|alias .*/library/;|alias ${base}/library/;|" \
+  -e "s|alias .*/cache/;|alias ${base}/cache/;|" /etc/angie/http.d/romm.conf
+SYNCEOF
+      chmod +x /usr/local/bin/romm-sync-angie-paths
+      mkdir -p /etc/systemd/system/angie.service.d
+      cat <<'DROPEOF' >/etc/systemd/system/angie.service.d/romm-paths.conf
+[Service]
+ExecStartPre=/usr/local/bin/romm-sync-angie-paths
+DROPEOF
+      systemctl daemon-reload
       systemctl reload angie
     elif [[ -f /etc/nginx/sites-available/romm ]]; then
       sed -i "s|alias .*/library/;|alias ${ROMM_BASE}/library/;|" /etc/nginx/sites-available/romm
       nginx_enable_site romm
     fi
+    if [[ -f /etc/systemd/system/romm-watcher.service ]]; then
+      sed -i "s|\(watcher\.py' \).*|\1\${ROMM_BASE_PATH}/library|" /etc/systemd/system/romm-watcher.service
+      systemctl daemon-reload
+    fi
     msg_ok "Updated ROMM"
 
     msg_info "Starting Services"

install/romm-install.sh

@@ -327,8 +327,22 @@ server {
 }
 EOF
 
-sed -i -e "s|alias /var/lib/romm/library/;|alias ${ROMM_BASE}/library/;|" \
-  -e "s|alias /var/lib/romm/cache/;|alias ${ROMM_BASE}/cache/;|" /etc/angie/http.d/romm.conf
+cat <<'SYNCEOF' >/usr/local/bin/romm-sync-angie-paths
+#!/usr/bin/env bash
+base="$(grep -m1 '^ROMM_BASE_PATH=' /opt/romm/.env 2>/dev/null | cut -d= -f2)"
+base="${base:-/var/lib/romm}"
+[[ -f /etc/angie/http.d/romm.conf ]] || exit 0
+sed -i -e "s|alias .*/library/;|alias ${base}/library/;|" \
+  -e "s|alias .*/cache/;|alias ${base}/cache/;|" /etc/angie/http.d/romm.conf
+SYNCEOF
+chmod +x /usr/local/bin/romm-sync-angie-paths
+mkdir -p /etc/systemd/system/angie.service.d
+cat <<'EOF' >/etc/systemd/system/angie.service.d/romm-paths.conf
+[Service]
+ExecStartPre=/usr/local/bin/romm-sync-angie-paths
+EOF
+systemctl daemon-reload
+/usr/local/bin/romm-sync-angie-paths
 rm -f /etc/angie/http.d/default.conf
 systemctl restart angie
 systemctl enable -q --now angie
@@ -405,7 +419,7 @@ Type=simple
 WorkingDirectory=/opt/romm/backend
 EnvironmentFile=/opt/romm/.env
 Environment="PYTHONPATH=/opt/romm/backend"
-ExecStart=/opt/romm/.venv/bin/watchfiles --target-type command '/opt/romm/.venv/bin/python watcher.py' /var/lib/romm/library
+ExecStart=/opt/romm/.venv/bin/watchfiles --target-type command '/opt/romm/.venv/bin/python watcher.py' \${ROMM_BASE_PATH}/library
 Restart=on-failure
 RestartSec=5