diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..1ae615c
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,228 @@
+name: CI
+
+on:
+  push:
+    branches: [main, develop]
+    tags:
+      - 'v*'
+  pull_request:
+    branches: [main, develop]
+  schedule:
+    - cron: '0 0 * * 0' # Weekly on Sunday (security scans)
+  workflow_dispatch:
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  # ── Phase 1: Lint ──────────────────────────────────────────────────────
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install Python linting tools
+        run: |
+          python -m pip install --upgrade pip
+          pip install black ruff mypy
+          pip install -r backend/requirements.txt
+
+      - name: Check code formatting with Black
+        run: black --check backend/
+
+      - name: Lint with Ruff
+        run: ruff check backend/
+
+      - name: Type check with mypy
+        run: mypy backend/app --ignore-missing-imports
+        continue-on-error: true
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '18'
+          cache: 'npm'
+          cache-dependency-path: frontend/package-lock.json
+
+      - name: Install frontend dependencies
+        run: npm ci
+        working-directory: frontend
+
+      - name: Lint frontend with ESLint
+        run: npm run lint
+        working-directory: frontend
+
+  # ── Phase 2: Test ──────────────────────────────────────────────────────
+  test:
+    name: Test
+    needs: lint
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+
+    services:
+      postgres:
+        image: postgres:15
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_DB: pop3_forwarder_test
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+        ports:
+          - 5432:5432
+
+      redis:
+        image: redis:7-alpine
+        options: >-
+          --health-cmd "redis-cli ping"
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+        ports:
+          - 6379:6379
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+          cache: 'pip'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r backend/requirements.txt
+          pip install pytest pytest-asyncio pytest-cov httpx
+
+      - name: Run tests with coverage
+        env:
+          DATABASE_URL: postgresql+asyncpg://postgres:postgres@localhost:5432/pop3_forwarder_test
+          REDIS_URL: redis://localhost:6379/0
+          SECRET_KEY: test-secret-key-for-ci-cd-at-least-32-chars
+          ENCRYPTION_KEY: test-encryption-key-for-ci-cd-at-least-32-chars
+        run: |
+          cd backend
+          pytest tests/ -v --cov=app --cov-report=xml --cov-report=term
+
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v3
+        with:
+          file: ./backend/coverage.xml
+          flags: unittests
+          name: codecov-umbrella
+          fail_ci_if_error: false
+
+  # ── Phase 3: Security ──────────────────────────────────────────────────
+  security:
+    name: Security
+    needs: test
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write
+      actions: read
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install bandit safety
+          pip install -r backend/requirements.txt
+
+      - name: Run Bandit security scan
+        run: bandit -r backend/app -ll
+        continue-on-error: true
+
+      - name: Check dependencies for known vulnerabilities
+        run: safety check --json
+        continue-on-error: true
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: python, javascript-typescript
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3
+
+  # ── Phase 4: Build ─────────────────────────────────────────────────────
+  build:
+    name: Build & Push Docker Image
+    needs: security
+    if: github.ref == 'refs/heads/main' || startsWith(github.ref, 'refs/tags/v')
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      id-token: write
+      attestations: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels)
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=sha,prefix={{branch}}-
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: Build and push Docker image
+        id: build-push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          platforms: linux/amd64,linux/arm64
+
+      - name: Generate artifact attestation
+        uses: actions/attest-build-provenance@v1
+        with:
+          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          subject-digest: ${{ steps.build-push.outputs.digest }}
+          push-to-registry: true
diff --git a/.github/workflows/docker-build.yml b/.github/workflows/docker-build.yml
deleted file mode 100644
index dee9a2c..0000000
--- a/.github/workflows/docker-build.yml
+++ /dev/null
@@ -1,74 +0,0 @@
-name: Build and Push Docker Image
-
-on:
-  push:
-    branches:
-      - main
-      - master
-    tags:
-      - 'v*'
-  pull_request:
-    branches:
-      - main
-      - master
-  workflow_dispatch:
-
-env:
-  REGISTRY: ghcr.io
-  IMAGE_NAME: ${{ github.repository }}
-
-jobs:
-  build-and-push:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-      packages: write
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
-
-      - name: Log in to Container Registry
-        if: github.event_name != 'pull_request'
-        uses: docker/login-action@v3
-        with:
-          registry: ${{ env.REGISTRY }}
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Extract metadata (tags, labels)
-        id: meta
-        uses: docker/metadata-action@v5
-        with:
-          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
-          tags: |
-            type=ref,event=branch
-            type=ref,event=pr
-            type=semver,pattern={{version}}
-            type=semver,pattern={{major}}.{{minor}}
-            type=semver,pattern={{major}}
-            type=sha,prefix={{branch}}-
-            type=raw,value=latest,enable={{is_default_branch}}
-
-      - name: Build and push Docker image
-        id: build
-        uses: docker/build-push-action@v5
-        with:
-          context: .
-          push: ${{ github.event_name != 'pull_request' }}
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
-          platforms: linux/amd64,linux/arm64
-
-      - name: Generate artifact attestation
-        if: github.event_name != 'pull_request'
-        uses: actions/attest-build-provenance@v1
-        with:
-          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
-          subject-digest: ${{ steps.build.outputs.digest }}
-          push-to-registry: true
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
deleted file mode 100644
index 54c7747..0000000
--- a/.github/workflows/lint.yml
+++ /dev/null
@@ -1,41 +0,0 @@
-name: Code Quality
-
-on:
-  push:
-    branches: [ main, develop ]
-  pull_request:
-    branches: [ main, develop ]
-
-jobs:
-  lint:
-    runs-on: ubuntu-latest
-    
-    permissions:
-      contents: read
-    
-    steps:
-    - uses: actions/checkout@v4
-    
-    - name: Set up Python
-      uses: actions/setup-python@v5
-      with:
-        python-version: '3.11'
-    
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install black ruff mypy
-        pip install -r backend/requirements.txt
-    
-    - name: Check code formatting with Black
-      run: |
-        black --check backend/
-    
-    - name: Lint with Ruff
-      run: |
-        ruff check backend/
-    
-    - name: Type check with mypy
-      run: |
-        mypy backend/app --ignore-missing-imports
-      continue-on-error: true
diff --git a/.github/workflows/security.yml b/.github/workflows/security.yml
deleted file mode 100644
index c2cd1b2..0000000
--- a/.github/workflows/security.yml
+++ /dev/null
@@ -1,50 +0,0 @@
-name: Security Scan
-
-on:
-  push:
-    branches: [ main, develop ]
-  pull_request:
-    branches: [ main, develop ]
-  schedule:
-    - cron: '0 0 * * 0'  # Weekly on Sunday
-
-jobs:
-  security:
-    runs-on: ubuntu-latest
-    
-    permissions:
-      contents: read
-      security-events: write  # For CodeQL
-      actions: read
-    
-    steps:
-    - uses: actions/checkout@v4
-    
-    - name: Set up Python
-      uses: actions/setup-python@v5
-      with:
-        python-version: '3.11'
-    
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install bandit safety
-        pip install -r backend/requirements.txt
-    
-    - name: Run Bandit security scan
-      run: |
-        bandit -r backend/app -ll
-      continue-on-error: true
-    
-    - name: Check dependencies for known vulnerabilities
-      run: |
-        safety check --json
-      continue-on-error: true
-    
-    - name: Run CodeQL Analysis
-      uses: github/codeql-action/init@v3
-      with:
-        languages: python
-    
-    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v3
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
deleted file mode 100644
index b02acb4..0000000
--- a/.github/workflows/test.yml
+++ /dev/null
@@ -1,73 +0,0 @@
-name: Tests
-
-on:
-  push:
-    branches: [ main, develop ]
-  pull_request:
-    branches: [ main, develop ]
-
-jobs:
-  test:
-    runs-on: ubuntu-latest
-    
-    permissions:
-      contents: read
-      pull-requests: write  # For coverage comments
-    
-    services:
-      postgres:
-        image: postgres:15
-        env:
-          POSTGRES_USER: postgres
-          POSTGRES_PASSWORD: postgres
-          POSTGRES_DB: pop3_forwarder_test
-        options: >-
-          --health-cmd pg_isready
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
-        ports:
-          - 5432:5432
-      
-      redis:
-        image: redis:7-alpine
-        options: >-
-          --health-cmd "redis-cli ping"
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
-        ports:
-          - 6379:6379
-    
-    steps:
-    - uses: actions/checkout@v4
-    
-    - name: Set up Python
-      uses: actions/setup-python@v5
-      with:
-        python-version: '3.11'
-        cache: 'pip'
-    
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install -r backend/requirements.txt
-        pip install pytest pytest-asyncio pytest-cov httpx
-    
-    - name: Run tests with coverage
-      env:
-        DATABASE_URL: postgresql+asyncpg://postgres:postgres@localhost:5432/pop3_forwarder_test
-        REDIS_URL: redis://localhost:6379/0
-        SECRET_KEY: test-secret-key-for-ci-cd-at-least-32-chars
-        ENCRYPTION_KEY: test-encryption-key-for-ci-cd-at-least-32-chars
-      run: |
-        cd backend
-        pytest tests/ -v --cov=app --cov-report=xml --cov-report=term
-    
-    - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v3
-      with:
-        file: ./backend/coverage.xml
-        flags: unittests
-        name: codecov-umbrella
-        fail_ci_if_error: false