fix: Disable wasm reference-types for compatibility with devices like iOS 16

[zxch3n]

Summary

• Strip the target_features custom section from the raw loro_wasm.wasm before running wasm-bindgen, so generated JS falls back to slab-based object handles instead of externref table glue.
• Add a reusable strip-custom command to loro-wasm-tools and use it in the loro-wasm build pipeline.
• Remove the old bundler externref table initialization patch, which is no longer needed after forcing slab mode.

Root Cause

wasm-bindgen 0.2.100 reads the wasm target_features custom section. When it sees +reference-types, it emits externref table glue. Safari 16.0-16.3 lacks WebAssembly reference-types support, which can surface as an out-of-bounds table access trap.

Validation

• git diff --check
• cargo check -p loro-wasm-tools
• pnpm -C crates/loro-wasm build-release
• Verified release artifacts contain 0 matches for externref, addToExternrefTable, and __wbindgen_init_externref_table across bundler, nodejs, web, and base64 outputs.
• Verified release wasm binaries contain 0 matches for target_features and reference-types.

[github-actions]

WASM Size Report

• Original size: 3138.80 KB
• Gzipped size: 992.67 KB
• Brotli size: 689.87 KB