test: add E2E tests with real PostgreSQL and Qdrant services

Why this change is needed:
While unit tests with mocks verify code logic, they cannot catch real-world
issues like database connectivity, SQL syntax errors, vector dimension mismatches,
or actual data migration failures. E2E tests with real database services provide
confidence that the feature works in production-like environments.

What this adds:
1. E2E workflow (.github/workflows/e2e-tests.yml):
   - PostgreSQL job with ankane/pgvector:latest service
   - Qdrant job with qdrant/qdrant:latest service
   - Runs on Python 3.10 and 3.12
   - Manual trigger + automatic on PR

2. PostgreSQL E2E tests (test_e2e_postgres_migration.py):
   - Fresh installation: Create new table with model suffix
   - Legacy migration: Migrate 10 real records from legacy table
   - Multi-model: Two models create separate tables with different dimensions
   - Tests real SQL execution, pgvector operations, data integrity

3. Qdrant E2E tests (test_e2e_qdrant_migration.py):
   - Fresh installation: Create new collection with model suffix
   - Legacy migration: Migrate 10 real vectors from legacy collection
   - Multi-model: Two models create separate collections (768d vs 1024d)
   - Tests real Qdrant API calls, collection creation, vector operations

How it solves it:
- Uses GitHub Actions services to spin up real databases
- Tests connect to actual PostgreSQL with pgvector extension
- Tests connect to actual Qdrant server with HTTP API
- Verifies complete data flow: create → migrate → verify
- Validates dimension isolation and data integrity

Impact:
- Catches database-specific issues before production
- Validates migration logic with real data
- Confirms multi-model isolation works end-to-end
- Provides high confidence for merge to main

Testing:
After this commit, E2E tests can be triggered manually from GitHub Actions UI:
  Actions → E2E Tests (Real Databases) → Run workflow

Expected results:
- PostgreSQL E2E: 3 tests pass (fresh install, migration, multi-model)
- Qdrant E2E: 3 tests pass (fresh install, migration, multi-model)
- Total: 6 E2E tests validating real database operations

Note:
E2E tests are separate from fast unit tests and only run on:
1. Manual trigger (workflow_dispatch)
2. Pull requests that modify storage implementation files
This keeps the main CI fast while providing thorough validation when needed.

.github/workflows/e2e-tests.yml

@@ -0,0 +1,181 @@
+name: E2E Tests (Real Databases)
+
+on:
+  workflow_dispatch:  # Manual trigger only for E2E tests
+  pull_request:
+    branches: [ main, dev ]
+    paths:
+      - 'lightrag/kg/postgres_impl.py'
+      - 'lightrag/kg/qdrant_impl.py'
+      - 'tests/test_e2e_*.py'
+
+jobs:
+  e2e-postgres:
+    name: E2E PostgreSQL Tests
+    runs-on: ubuntu-latest
+
+    services:
+      postgres:
+        image: ankane/pgvector:latest
+        env:
+          POSTGRES_USER: lightrag
+          POSTGRES_PASSWORD: lightrag_test_password
+          POSTGRES_DB: lightrag_test
+        ports:
+          - 5432:5432
+        options: >-
+          --health-cmd "pg_isready -U lightrag"
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+
+    strategy:
+      matrix:
+        python-version: ['3.10', '3.12']
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Cache pip packages
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-e2e-${{ hashFiles('**/pyproject.toml') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-e2e-
+          ${{ runner.os }}-pip-
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -e ".[api]"
+        pip install pytest pytest-asyncio asyncpg numpy
+
+    - name: Wait for PostgreSQL
+      run: |
+        timeout 30 bash -c 'until pg_isready -h localhost -p 5432 -U lightrag; do sleep 1; done'
+
+    - name: Setup pgvector extension
+      env:
+        PGPASSWORD: lightrag_test_password
+      run: |
+        psql -h localhost -U lightrag -d lightrag_test -c "CREATE EXTENSION IF NOT EXISTS vector;"
+        psql -h localhost -U lightrag -d lightrag_test -c "SELECT extname, extversion FROM pg_extension WHERE extname = 'vector';"
+
+    - name: Run PostgreSQL E2E tests
+      env:
+        POSTGRES_HOST: localhost
+        POSTGRES_PORT: 5432
+        POSTGRES_USER: lightrag
+        POSTGRES_PASSWORD: lightrag_test_password
+        POSTGRES_DB: lightrag_test
+        POSTGRES_WORKSPACE: e2e_test
+      run: |
+        pytest tests/test_e2e_postgres_migration.py -v --tb=short -s
+      timeout-minutes: 10
+
+    - name: Upload PostgreSQL test results
+      if: always()
+      uses: actions/upload-artifact@v4
+      with:
+        name: e2e-postgres-results-py${{ matrix.python-version }}
+        path: |
+          .pytest_cache/
+          test-results.xml
+        retention-days: 7
+
+  e2e-qdrant:
+    name: E2E Qdrant Tests
+    runs-on: ubuntu-latest
+
+    services:
+      qdrant:
+        image: qdrant/qdrant:latest
+        ports:
+          - 6333:6333
+          - 6334:6334
+        options: >-
+          --health-cmd "curl -f http://localhost:6333/health || exit 1"
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+
+    strategy:
+      matrix:
+        python-version: ['3.10', '3.12']
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Cache pip packages
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-e2e-${{ hashFiles('**/pyproject.toml') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-e2e-
+          ${{ runner.os }}-pip-
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -e ".[api]"
+        pip install pytest pytest-asyncio qdrant-client numpy
+
+    - name: Wait for Qdrant
+      run: |
+        timeout 30 bash -c 'until curl -f http://localhost:6333/health > /dev/null 2>&1; do sleep 1; done'
+        echo "Qdrant is ready"
+
+    - name: Verify Qdrant connection
+      run: |
+        curl -X GET "http://localhost:6333/collections" -H "Content-Type: application/json"
+
+    - name: Run Qdrant E2E tests
+      env:
+        QDRANT_URL: http://localhost:6333
+        QDRANT_API_KEY: ""
+      run: |
+        pytest tests/test_e2e_qdrant_migration.py -v --tb=short -s
+      timeout-minutes: 10
+
+    - name: Upload Qdrant test results
+      if: always()
+      uses: actions/upload-artifact@v4
+      with:
+        name: e2e-qdrant-results-py${{ matrix.python-version }}
+        path: |
+          .pytest_cache/
+          test-results.xml
+        retention-days: 7
+
+  e2e-summary:
+    name: E2E Test Summary
+    runs-on: ubuntu-latest
+    needs: [e2e-postgres, e2e-qdrant]
+    if: always()
+
+    steps:
+    - name: Check test results
+      run: |
+        echo "## E2E Test Summary" >> $GITHUB_STEP_SUMMARY
+        echo "" >> $GITHUB_STEP_SUMMARY
+        echo "### PostgreSQL E2E Tests" >> $GITHUB_STEP_SUMMARY
+        echo "Status: ${{ needs.e2e-postgres.result }}" >> $GITHUB_STEP_SUMMARY
+        echo "" >> $GITHUB_STEP_SUMMARY
+        echo "### Qdrant E2E Tests" >> $GITHUB_STEP_SUMMARY
+        echo "Status: ${{ needs.e2e-qdrant.result }}" >> $GITHUB_STEP_SUMMARY
+
+    - name: Fail if any test failed
+      if: needs.e2e-postgres.result != 'success' || needs.e2e-qdrant.result != 'success'
+      run: exit 1