taprpc+scripts: detect Podman wrapper and preserve Docker UID mapping

Detect Podman by checking "$DOCKER --version", allowing overrides via
the DOCKER environment variable. Retain "--user $UID:$(id -g)" for
Docker/CI to ensure generated files are user-owned. For Podman, switch
to "--user=0:0" to avoid EACCES errors caused by rootless subuid/subgid
remapping on bind mounts.

- scripts/gen_sqlc_docker.sh: add runtime user selection; use $DOCKER
  for run
- taprpc/gen_protos_docker.sh: same detection logic; use $DOCKER for
  build/run

Fixes "Permission denied" errors with rootless Podman, while maintaining
existing Docker behavior.

Author: ffranr

scripts/gen_sqlc_docker.sh

@@ -2,6 +2,13 @@
 
 set -e
 
+# Use docker by default; allow overrides and detect podman wrapper.
+DOCKER=${DOCKER:-docker}
+user_args=(--user "$UID:$(id -g)")
+if $DOCKER --version 2>/dev/null | grep -qi podman; then
+	user_args=(--user=0:0)
+fi
+
 # restore_files is a function to restore original schema files.
 restore_files() {
 	echo "Restoring SQLite bigint patch..."
@@ -40,9 +47,9 @@ echo "Generating sql models and queries in go..."
 
 # Run the script to generate the new generated code. Once the script exits, we
 # use `trap` to make sure all files are restored.
-docker run \
+$DOCKER run \
 	--rm \
-	--user "$UID:$(id -g)" \
+	"${user_args[@]}" \
 	-e UID=$UID \
 	-v "$DIR/../:/build" \
 	-w /build \

taprpc/gen_protos_docker.sh

@@ -2,6 +2,13 @@
 
 set -e
 
+# Use docker by default; allow overrides and detect podman wrapper.
+DOCKER=${DOCKER:-docker}
+user_args=(--user "$UID:$(id -g)")
+if $DOCKER --version 2>/dev/null | grep -qi podman; then
+  user_args=(--user=0:0)
+fi
+
 # Directory of the script file, independent of where it's called from.
 DIR="$(cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd)"
 
@@ -10,16 +17,16 @@ GRPC_GATEWAY_VERSION=$(go list -f '{{.Version}}' -m github.com/grpc-ecosystem/gr
 LND_VERSION=$(go list -f '{{.Version}}' -m github.com/lightningnetwork/lnd)
 
 echo "Building protobuf compiler docker image..."
-docker build -t taproot-assets-protobuf-builder \
+$DOCKER build -t taproot-assets-protobuf-builder \
   --build-arg PROTOBUF_VERSION="$PROTOBUF_VERSION" \
   --build-arg GRPC_GATEWAY_VERSION="$GRPC_GATEWAY_VERSION" \
   --build-arg LND_VERSION="$LND_VERSION" \
   .
 
 echo "Compiling and formatting *.proto files..."
-docker run \
+$DOCKER run \
   --rm \
-  --user "$UID:$(id -g)" \
+  "${user_args[@]}" \
   -e UID=$UID \
   -e COMPILE_MOBILE \
   -e SUBSERVER_PREFIX \