phase 5: wasm core, GalaxyClient skeleton, Connect-Web stubs

Compile `ui/core` to WebAssembly via TinyGo (903 KB) and expose four
canonical-bytes / signature-verification functions on
`globalThis.galaxyCore` from `ui/wasm/main.go`. The TypeScript-side
`Core` interface plus a `WasmCore` adapter (browser + JSDOM loader)
bridge those into a typed shape, and a `GalaxyClient` skeleton wires
`Core.signRequest` → injected `Signer` → typed Connect client →
`Core.verifyPayloadHash` / `verifyResponse`.

Wire `ui/buf.gen.yaml` against the local
`@bufbuild/protoc-gen-es` v2 binary (devDependency) so the codegen
step does not depend on the buf.build BSR. Vitest covers the bridge
end-to-end: per-method WasmCore tests under JSDOM, byte-for-byte
canon parity against the gateway fixtures committed in Phase 3, and
a `GalaxyClient` orchestration test using
`createRouterTransport`. The committed `core.wasm` snapshot tracks
TinyGo output so contributors run `make wasm` only when `ui/core/`
changes; CI consumes the snapshot directly.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ui/.gitignore

@@ -7,8 +7,12 @@ node_modules/
 build/
 dist/
 
-# Generated WASM bundles
+# Generated WASM bundles. The committed `frontend/static/core.wasm`
+# (built by `make wasm` from `ui/wasm/`) is intentionally tracked so
+# Vitest and the SvelteKit dev server have the artefact available
+# without forcing every contributor to install TinyGo locally.
 *.wasm
+!frontend/static/core.wasm
 
 # Wails desktop wrapper (Phase 31+)
 desktop/build/