diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0ab6fc1c1..bcbf71c29 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -56,8 +56,11 @@ jobs:
         with:
           node-version: '20'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v6
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Verify pnpm version
+        run: pnpm --version
 
       - name: Get pnpm store directory
         shell: bash
@@ -68,9 +71,9 @@ jobs:
         uses: actions/cache@v5
         with:
           path: ${{ env.STORE_PATH }}
-          key: ${{ runner.os }}-pnpm-store-v2-${{ hashFiles('**/pnpm-lock.yaml') }}
+          key: ${{ runner.os }}-pnpm-store-v3-${{ hashFiles('**/pnpm-lock.yaml') }}
           restore-keys: |
-            ${{ runner.os }}-pnpm-store-v2-
+            ${{ runner.os }}-pnpm-store-v3-
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
@@ -105,8 +108,11 @@ jobs:
         with:
           node-version: '20'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v6
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Verify pnpm version
+        run: pnpm --version
 
       - name: Get pnpm store directory
         shell: bash
@@ -117,9 +123,9 @@ jobs:
         uses: actions/cache@v5
         with:
           path: ${{ env.STORE_PATH }}
-          key: ${{ runner.os }}-pnpm-store-v2-${{ hashFiles('**/pnpm-lock.yaml') }}
+          key: ${{ runner.os }}-pnpm-store-v3-${{ hashFiles('**/pnpm-lock.yaml') }}
           restore-keys: |
-            ${{ runner.os }}-pnpm-store-v2-
+            ${{ runner.os }}-pnpm-store-v3-
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
@@ -168,8 +174,11 @@ jobs:
         with:
           node-version: '20'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v6
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Verify pnpm version
+        run: pnpm --version
 
       - name: Get pnpm store directory
         shell: bash
@@ -180,9 +189,9 @@ jobs:
         uses: actions/cache@v5
         with:
           path: ${{ env.STORE_PATH }}
-          key: ${{ runner.os }}-pnpm-store-v2-${{ hashFiles('**/pnpm-lock.yaml') }}
+          key: ${{ runner.os }}-pnpm-store-v3-${{ hashFiles('**/pnpm-lock.yaml') }}
           restore-keys: |
-            ${{ runner.os }}-pnpm-store-v2-
+            ${{ runner.os }}-pnpm-store-v3-
       
       - name: Setup Next.js cache
         uses: actions/cache@v5
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 839f925b0..5ec270dc4 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -24,8 +24,11 @@ jobs:
         with:
           node-version: '20'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v6
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Verify pnpm version
+        run: pnpm --version
 
       - name: Get pnpm store directory
         shell: bash
@@ -36,9 +39,9 @@ jobs:
         uses: actions/cache@v5
         with:
           path: ${{ env.STORE_PATH }}
-          key: ${{ runner.os }}-pnpm-store-v2-${{ hashFiles('**/pnpm-lock.yaml') }}
+          key: ${{ runner.os }}-pnpm-store-v3-${{ hashFiles('**/pnpm-lock.yaml') }}
           restore-keys: |
-            ${{ runner.os }}-pnpm-store-v2-
+            ${{ runner.os }}-pnpm-store-v3-
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
diff --git a/.github/workflows/pr-automation.yml b/.github/workflows/pr-automation.yml
index d755f525d..295b6c1f6 100644
--- a/.github/workflows/pr-automation.yml
+++ b/.github/workflows/pr-automation.yml
@@ -65,8 +65,8 @@ jobs:
         with:
           node-version: '20'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v6
+      - name: Enable Corepack
+        run: corepack enable
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 89a894973..aa6cbbae6 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -23,8 +23,11 @@ jobs:
         with:
           node-version: '20'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v6
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Verify pnpm version
+        run: pnpm --version
 
       - name: Get pnpm store directory
         shell: bash
@@ -35,9 +38,9 @@ jobs:
         uses: actions/cache@v5
         with:
           path: ${{ env.STORE_PATH }}
-          key: ${{ runner.os }}-pnpm-store-v2-${{ hashFiles('**/pnpm-lock.yaml') }}
+          key: ${{ runner.os }}-pnpm-store-v3-${{ hashFiles('**/pnpm-lock.yaml') }}
           restore-keys: |
-            ${{ runner.os }}-pnpm-store-v2-
+            ${{ runner.os }}-pnpm-store-v3-
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
diff --git a/.github/workflows/validate-deps.yml b/.github/workflows/validate-deps.yml
index 763ac8380..24f7c0c6e 100644
--- a/.github/workflows/validate-deps.yml
+++ b/.github/workflows/validate-deps.yml
@@ -27,8 +27,11 @@ jobs:
         with:
           node-version: '20'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v6
+      - name: Enable Corepack
+        run: corepack enable
+
+      - name: Verify pnpm version
+        run: pnpm --version
 
       - name: Get pnpm store directory
         shell: bash
@@ -39,9 +42,9 @@ jobs:
         uses: actions/cache@v5
         with:
           path: ${{ env.STORE_PATH }}
-          key: ${{ runner.os }}-pnpm-store-v2-${{ hashFiles('**/pnpm-lock.yaml') }}
+          key: ${{ runner.os }}-pnpm-store-v3-${{ hashFiles('**/pnpm-lock.yaml') }}
           restore-keys: |
-            ${{ runner.os }}-pnpm-store-v2-
+            ${{ runner.os }}-pnpm-store-v3-
 
       - name: Verify lockfile is up to date
         run: |
diff --git a/CHANGELOG.md b/CHANGELOG.md
index cc9fee86a..44551ab01 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Fixed
+- **CI: Replace `pnpm/action-setup@v6` with corepack** — Switched all GitHub Actions workflows (`ci.yml`, `lint.yml`, `release.yml`, `validate-deps.yml`, `pr-automation.yml`) from `pnpm/action-setup@v6` to `corepack enable` to fix persistent `ERR_PNPM_BROKEN_LOCKFILE` errors. Corepack reads the exact `packageManager` field from `package.json` (including SHA verification), ensuring the correct pnpm version is used in CI. Also bumped pnpm store cache keys to v3 and added a pnpm version verification step.
 - **Broken pnpm lockfile** — Regenerated `pnpm-lock.yaml` from scratch to fix `ERR_PNPM_BROKEN_LOCKFILE` ("expected a single document in the stream, but found more") that was causing all CI jobs to fail. The previous merge of PR #1117 only included workflow cache key changes but did not carry over the regenerated lockfile.
 
 ### Added