wasm: migrate to upstream ruby-rbs on all targets; land Phase 0 browser spike

Drop the rubys/rbs-rust fork: roundhouse now depends on the published ruby-rbs = "0.3" on every target. wasm only needs ruby-rbs-sys built for wasm32 — its vendored RBS C parser compiled by the WASI-SDK clang, and its bindgen run against the host target (#[repr(C)] is layout-portable), sidestepping the libclang-version-fragile bindgen-against-wasm failures.

That build.rs support is upstreamed as ruby/rbs#2992; until it publishes, wasm/Cargo.toml carries a temporary [patch.crates-io] ruby-rbs-sys local path (repin once merged). Build requires WASI_SDK_PATH=/opt/wasi-sdk.

Also lands the rung-A Phase 0 browser spike (wasm/browser-spike/): a shared wasi-shim.mjs + transpile.mjs driving both the Node validator and a static browser page — proving the compiler transpiles real-blog in a real tab with no WebContainer/npm/bundler. Plus docs/browser-demo-plan.md.

Verified: native cargo check --lib clean; wasm build clean (3.2 MB); node round-trip OK.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: rubys

Cargo.lock

@@ -16,6 +16,7 @@ serde_json = "1"
 serde_yaml_ng = "0.10"
 indexmap = { version = "2", features = ["serde"] }
 ruby-prism = "1.9.0"
+ruby-rbs = "0.3"
 
 [target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]
 # (none yet)
@@ -35,9 +36,3 @@ version = "1"
 version = "2"
 default-features = false
 features = ["deflate"]
-
-[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
-ruby-rbs = "0.3"
-
-[target.'cfg(target_arch = "wasm32")'.dependencies]
-ruby-rbs-local = { package = "ruby-rbs", git = "https://github.com/rubys/rbs-rust" }

Cargo.toml

@@ -4,9 +4,6 @@
 //! serializable core with a Rails dialect layered on top. The IR is the
 //! deliverable; ingesters produce it, emitters consume it.
 
-#[cfg(target_arch = "wasm32")]
-extern crate ruby_rbs_local as ruby_rbs;
-
 pub mod adapter;
 pub mod analyze;
 pub mod app;