fix: [nomad-prep] P10 — audit lib/ + compose for docker-backend-isms (#797)

Sites touched:
- lib/generators.sh: WOODPECKER_BACKEND_DOCKER_NETWORK now reads from
  ${WOODPECKER_CI_NETWORK:-disinto_disinto-net} so nomad jobspecs can
  override the compose-generated network name.
- lib/forge-setup.sh: bare-mode _forgejo_exec() and setup_forge() use
  ${FORGEJO_CONTAINER_NAME:-disinto-forgejo} instead of hardcoding the
  container name. Compose mode is unaffected (uses service name).

Documented exceptions (container_name directives in generators.sh
compose template output): these define names inside docker-compose.yml,
which is compose-specific output. Under nomad the generator is not used.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/forge-setup.sh

@@ -31,8 +31,9 @@ _load_init_context() {
 # Execute a command in the Forgejo container (for admin operations)
 _forgejo_exec() {
   local use_bare="${DISINTO_BARE:-false}"
+  local cname="${FORGEJO_CONTAINER_NAME:-disinto-forgejo}"
   if [ "$use_bare" = true ]; then
-    docker exec -u git disinto-forgejo "$@"
+    docker exec -u git "$cname" "$@"
   else
     docker compose -f "${FACTORY_ROOT}/docker-compose.yml" exec -T -u git forgejo "$@"
   fi
@@ -94,11 +95,12 @@ setup_forge() {
       # Bare-metal mode: standalone docker run
       mkdir -p "${FORGEJO_DATA_DIR}"
 
-      if docker ps -a --format '{{.Names}}' | grep -q '^disinto-forgejo$'; then
-        docker start disinto-forgejo >/dev/null 2>&1 || true
+      local cname="${FORGEJO_CONTAINER_NAME:-disinto-forgejo}"
+      if docker ps -a --format '{{.Names}}' | grep -q "^${cname}$"; then
+        docker start "$cname" >/dev/null 2>&1 || true
       else
         docker run -d \
-          --name disinto-forgejo \
+          --name "$cname" \
           --restart unless-stopped \
           -p "${forge_port}:3000" \
           -p 2222:22 \

lib/generators.sh

@@ -318,7 +318,7 @@ services:
       WOODPECKER_AGENT_SECRET: ${WOODPECKER_AGENT_SECRET:-}
       WOODPECKER_GRPC_SECURE: "false"
       WOODPECKER_HEALTHCHECK_ADDR: ":3333"
-      WOODPECKER_BACKEND_DOCKER_NETWORK: disinto_disinto-net
+      WOODPECKER_BACKEND_DOCKER_NETWORK: ${WOODPECKER_CI_NETWORK:-disinto_disinto-net}
       WOODPECKER_MAX_WORKFLOWS: 1
     healthcheck:
       test: ["CMD", "wget", "-q", "--spider", "http://localhost:3333/healthz"]