Fix CI workflows to use Yarn 4 (Berry) with corepack

- Add packageManager field to package.json for corepack
- Add .yarnrc.yml with node-modules linker
- Update all workflows to use corepack enable + yarn --immutable
- Remove yarn cache from actions/setup-node (incompatible with Yarn 4)

.github/workflows/ci.yml

@@ -18,10 +18,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '18'
-          cache: 'yarn'
+
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Generate types
         run: yarn codegen

.github/workflows/code-quality.yml

@@ -19,10 +19,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '18'
-          cache: 'yarn'
+
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Run ESLint
         run: yarn eslint src/ --ext .ts --max-warnings 0
@@ -40,10 +42,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '18'
-          cache: 'yarn'
+
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Check formatting
         run: yarn prettier --check "src/**/*.ts"
@@ -60,10 +64,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '18'
-          cache: 'yarn'
+
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Generate types
         run: yarn codegen

.github/workflows/deploy.yml

@@ -31,10 +31,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '18'
-          cache: 'yarn'
+
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Generate types
         run: yarn codegen
@@ -57,10 +59,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '18'
-          cache: 'yarn'
+
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Generate types
         run: yarn codegen

.github/workflows/security.yml

@@ -30,10 +30,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '18'
-          cache: 'yarn'
+
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Build
         run: yarn build
@@ -53,10 +55,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: '18'
-          cache: 'yarn'
+
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Run npm audit
         run: yarn npm audit --all --recursive || true

.yarnrc.yml

@@ -0,0 +1 @@
+nodeLinker: node-modules

package.json

@@ -1,6 +1,7 @@
 {
   "name": "subquery-pezkuwi",
   "version": "1.0.0",
+  "packageManager": "yarn@4.12.0",
   "description": "Pezkuwi SubQuery - Staking rewards, NominationPools, transfers indexer for PezWallet",
   "main": "dist/index.js",
   "scripts": {