chore: Move core tests into apps/core (OSS Migration) [LET-4169] (#4376)

* add a bunch of test to oss

* symlink and auto-detect dir

* symlink the other direction

* add pull_request_target logic

* remove undertaker and add alembic validation

* symlink doesn't work with gh actions and add validation workflow to ensure actions in cloud and oss are lockstep

* sync these

* specify extras selectively

.github/workflows/alembic-validation.yml

@@ -0,0 +1,113 @@
+name: Alembic Migration Validation
+
+on:
+  pull_request:
+    branches: [ main ]
+  pull_request_target:
+    branches: [ main ]
+    types: [labeled]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
+
+jobs:
+  changed-files:
+    # Run on pull_request OR on pull_request_target only when labeled "safe to test"
+    if: github.event_name == 'pull_request' || (github.event_name == 'pull_request_target' && contains(github.event.pull_request.labels.*.name, 'safe to test'))
+    runs-on: ubuntu-latest
+    name: changed-files
+    outputs:
+      all_changed_files: ${{ steps.changed-files.outputs.all_changed_files }}
+      any_changed: ${{ steps.changed-files.outputs.any_changed }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Get changed files
+        id: changed-files
+        uses: tj-actions/changed-files@v44
+        with:
+          files: |
+            apps/core/alembic/**
+            .github/workflows/alembic-validation.yml
+
+  test-sqlite:
+    needs: [ changed-files ]
+    if: ${{ needs.changed-files.outputs.any_changed == 'true' }}
+    runs-on: [self-hosted, medium]
+    timeout-minutes: 15
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Install dependencies
+        shell: bash
+        working-directory: apps/core
+        run: uv sync --no-install-project ${{ inputs.install-args || '--extra sqlite --extra external-tools --extra dev --extra cloud-tool-sandbox' }}
+      - name: Test alembic migration
+        working-directory: apps/core
+        run: |
+          uv run alembic upgrade head
+          # kinda janky but I think this might not matter for sqlite?
+          # uv run alembic check
+
+      - name: Cleanup persistent data
+        if: ${{ always() }}
+        working-directory: apps/core
+        run: |
+          echo "Cleaning up persistent data..."
+          sudo rm -rf ~/.letta || true
+
+  test-postgres:
+    needs: [ changed-files ]
+    if: ${{ needs.changed-files.outputs.any_changed == 'true' }}
+    runs-on: [self-hosted, medium]
+    timeout-minutes: 15
+    services:
+      postgres:
+        image: pgvector/pgvector:pg17
+        ports:
+          - 5432:5432
+        env:
+          POSTGRES_HOST_AUTH_METHOD: trust
+          POSTGRES_DB: postgres
+          POSTGRES_USER: postgres
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Install dependencies
+        shell: bash
+        working-directory: apps/core
+        run: uv sync --no-install-project ${{ inputs.install-args || '--extra postgres --extra external-tools --extra dev --extra cloud-tool-sandbox' }}
+      - name: Test alembic migration
+        working-directory: apps/core
+        env:
+          LETTA_PG_PORT: 5432
+          LETTA_PG_USER: postgres
+          LETTA_PG_PASSWORD: postgres
+          LETTA_PG_DB: postgres
+          LETTA_PG_HOST: localhost
+        run: |
+          psql -h localhost -U postgres -d postgres -c 'CREATE EXTENSION IF NOT EXISTS vector;'
+          uv run alembic upgrade head
+          uv run alembic check
+
+      - name: Print docker logs if tests fail
+        if: ${{ failure() || cancelled() }}
+        run: |
+          echo "Printing Docker Logs..."
+          docker logs $(docker ps -aq --filter "ancestor=pgvector/pgvector:pg17") || true
+
+      - name: Cleanup containers and volumes
+        if: ${{ always() }}
+        run: |
+          echo "Cleaning up containers and volumes..."
+          docker stop $(docker ps -aq --filter "ancestor=pgvector/pgvector:pg17") || true
+          docker rm $(docker ps -aq --filter "ancestor=pgvector/pgvector:pg17") || true
+          docker volume prune -f || true
+          docker system prune -f || true