Add .gitignore for MoonBit

MoonBit.gitignore

@@ -0,0 +1,29 @@
+# Build System Artifacts
+_build/            # MoonBit default build output directory.
+.mooncakes/        # Local MoonBit package cache directory.
+
+# Coverage and Test Artifacts
+moonbit-coverage-*.txt # Coverage reports generated by MoonBit tooling.
+_coverage          # Coverage output directory used by coverage commands.
+bisect.coverage    # Bisect runtime coverage data file.
+
+# JavaScript Target Artifacts
+# *.js             # Uncomment if generated JavaScript should be ignored.
+*.js.map           # Source map files generated for JavaScript output.
+node_modules/      # Node.js dependencies used in JS target workflows.
+
+# WebAssembly Target Artifacts
+*.wasm             # Compiled WebAssembly binaries.
+*.wat              # WebAssembly text format output.
+
+# MoonBit Pilot / Agent Artifacts
+.moonagent/        # MoonBit agent runtime state and temporary files.
+
+# LLVM Backend Artifacts
+*.ll               # LLVM textual intermediate representation (IR) files.
+*.bc               # LLVM bitcode files.
+*.o                # Native object files from LLVM/native compilation.
+*.s                # Generated assembly source files.
+*.out              # Default executable output name on Unix-like systems.
+*.exe              # Native executable output on Windows.
+*.dSYM/            # macOS debug symbol bundles.