fix(moonbit): register toolchain and fix component build pipeline

MODULE.bazel

@@ -23,13 +23,14 @@ bazel_dep(name = "rules_cc", version = "0.2.14")
 bazel_dep(name = "rules_go", version = "0.59.0")
 
 # MoonBit language support for WebAssembly components
-# Required for moonbit_wasm_cli and moonbit_wasm_binary rules
-# Note: rules_moonbit is not yet in BCR - uses git_override
-bazel_dep(name = "rules_moonbit", version = "0.1.0")
+# Dev dependency: rules_moonbit is not yet in BCR. Downstream users who want
+# MoonBit support must add their own bazel_dep + git_override for rules_moonbit.
+# The moonbit/ rules are available but only resolve when rules_moonbit is present.
+bazel_dep(name = "rules_moonbit", version = "0.1.0", dev_dependency = True)
 git_override(
     module_name = "rules_moonbit",
     remote = "https://github.com/pulseengine/rules_moonbit.git",
-    commit = "b5bbfe8ef1f87b42c77f168640817f67ed8758a3",
+    commit = "e95c912e55094b90b6c02a6052c0a284b142e6b8",  # includes chmod + bundle + dev_dependency fix
 )
 
 # OCI image signing capabilities
@@ -241,6 +242,12 @@ use_repo(componentize_py, "componentize_py_toolchain")
 
 register_toolchains("@componentize_py_toolchain//:componentize_py_toolchain")
 
+# MoonBit hermetic toolchain for WebAssembly component builds (dev only)
+moonbit = use_extension("@rules_moonbit//moonbit:extensions.bzl", "moonbit_toolchain_extension", dev_dependency = True)
+use_repo(moonbit, "moonbit_toolchain")
+
+register_toolchains("@moonbit_toolchain//:moonbit_toolchain", dev_dependency = True)
+
 # File Operations Component toolchain for universal file handling
 register_toolchains("//toolchains:file_ops_toolchain_target")
 

moonbit/private/moonbit_wasm_component.bzl

@@ -46,6 +46,7 @@ def _moonbit_wasm_component_impl(ctx):
 
     moonbit_toolchain = ctx.toolchains["@rules_moonbit//moonbit:moonbit_toolchain_type"]
     moon = moonbit_toolchain.moonbit.moon_executable
+    moonbit_all_files = moonbit_toolchain.moonbit.all_files
 
     wit_file = ctx.file.wit
     srcs = ctx.files.srcs
@@ -70,6 +71,12 @@ WIT_FILE="$(pwd)/{wit_file}"
 OUTPUT="$(pwd)/{output}"
 ORIG_DIR="$(pwd)"
 
+# Set MOON_HOME so moon build can find the core library
+# MOON path: /path/to/external/moonbit_toolchain/bin/moon
+# MOON_HOME: /path/to/external/moonbit_toolchain/.moon
+TOOLCHAIN_ROOT=$(dirname $(dirname "$MOON"))
+export MOON_HOME="$TOOLCHAIN_ROOT/.moon"
+
 # Create temporary project directory
 PROJECT_DIR=$(mktemp -d)
 cleanup() {{ rm -rf "$PROJECT_DIR"; }}
@@ -94,7 +101,7 @@ if [ -d "$STUB_DIR" ]; then
 fi
 
 # Step 3: Compile with MoonBit
-"$MOON" build --target wasm --release 2>&1 || {{
+"$MOON" build --target wasm 2>&1 || {{
     echo "MoonBit compilation failed" >&2
     exit 1
 }}
@@ -107,7 +114,9 @@ if [ -z "$CORE_WASM" ]; then
 fi
 
 # Step 4: Embed WIT metadata
+# Use --encoding utf16 for MoonBit string encoding
 "$WASM_TOOLS" component embed \\
+    --encoding utf16 \\
     --world {world} \\
     "$WIT_FILE" \\
     "$CORE_WASM" \\
@@ -135,7 +144,7 @@ echo "Created component: $OUTPUT"
 
     ctx.actions.run_shell(
         command = script,
-        inputs = [wit_file, wit_bindgen, moon, wasm_tools] + srcs,
+        inputs = [wit_file, wit_bindgen, moon, wasm_tools] + srcs + moonbit_all_files.to_list(),
         outputs = [component_wasm],
         mnemonic = "MoonbitWasmComponent",
         progress_message = "Building MoonBit WASM component %s" % ctx.label,