Switch the app from npm to Yarn (Berry 4)

.github/workflows/deploy.yml

@@ -32,7 +32,7 @@ jobs:
             ~/.cargo/git
             ~/.cargo/bin
             wasm/target
-          key: ${{ runner.os }}-cargo-${{ hashFiles('wasm/Cargo.toml', 'app/package-lock.json') }}
+          key: ${{ runner.os }}-cargo-${{ hashFiles('wasm/Cargo.toml', 'app/yarn.lock') }}
 
       - name: Install wasm-pack
         run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
@@ -45,21 +45,22 @@ jobs:
         with:
           node-version: 22
 
-      # `npm install` pulls `comline-simulator` (the sim engine) as a git
-      # dependency and builds its WASM in `prepare` — lean `pkg/` + scripted
+      # `yarn install` pulls `comline-simulator` (the sim engine) as a git
+      # dependency and builds its WASM in `prepack` — lean `pkg/` + scripted
       # `pkg-script/`. The runner has cargo + wasm-opt; the cargo cache above
-      # keeps the one-time wasm-bindgen-cli build.
+      # keeps the one-time wasm-bindgen-cli build. Yarn is the runner's 1.x,
+      # which delegates to the committed `.yarn/releases/` (Yarn 4).
       - name: Install
         working-directory: app
-        run: npm install
+        run: yarn install
 
       - name: Test (simulate view)
         working-directory: app
-        run: npm test
+        run: yarn test
 
       - name: Build site
         working-directory: app
-        run: npm run build
+        run: yarn build
 
       - uses: actions/upload-pages-artifact@v3
         with:

.gitignore

@@ -1,13 +1,22 @@
-# Rust — the editor wasm crate (the sim engine is an npm git dependency now)
+# Rust — the editor wasm crate (the sim engine is a git dependency now)
 /wasm/target
 Cargo.lock
 
 # Node / Vite
 node_modules
 /app/dist
 
-# wasm-pack output for the editor wasm (regenerated by `npm run wasm` / CI)
+# wasm-pack output for the editor wasm (regenerated by `yarn wasm` / CI)
 /app/src/wasm
 
+# Yarn Berry (app/) — keep the pinned release, drop the rest
+/app/.yarn/*
+!/app/.yarn/patches
+!/app/.yarn/plugins
+!/app/.yarn/releases
+!/app/.yarn/sdks
+!/app/.yarn/versions
+/app/.pnp.*
+
 .DS_Store
 .idea/

app/.yarnrc.yml

@@ -0,0 +1,14 @@
+yarnPath: .yarn/releases/yarn-4.18.0.cjs
+nodeLinker: node-modules
+
+# `comline-simulator` is the sim engine — fetched from git and built to WASM in
+# its `prepack`/`prepare` on install. Yarn 4 gates git deps behind this
+# allow-list and disables lifecycle scripts by default; the build needs both on.
+approvedGitRepositories:
+  - "https://github.com/ComlineProject/simulator.git"
+enableScripts: true
+
+# That WASM build isn't byte-reproducible (wasm-opt runs only where it's
+# installed), so the git dep's tarball checksum drifts between machines — let
+# Yarn refresh it instead of failing the install.
+checksumBehavior: update