chore: remove CodeFlash integration (#11670)

Remove CodeFlash dependency, CI workflow, and configuration as it is no longer used.

.github/workflows/codeflash.yml

@@ -1,37 +0,0 @@
-name: Codeflash
-
-on:
-  pull_request:
-    paths:
-      - "src/backend/base/langflow/**"
-  workflow_dispatch:
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  optimize:
-    name: Optimize new Python code in this PR
-    if: ${{ github.actor != 'codeflash-ai[bot]' }}
-    runs-on: ubuntu-latest
-    env:
-      CODEFLASH_API_KEY: ${{ secrets.CODEFLASH_API_KEY }}
-      CODEFLASH_PR_NUMBER: ${{ github.event.number }}
-    steps:
-      - uses: actions/checkout@v6
-        with:
-          fetch-depth: 0
-      - name: "Setup Environment"
-        uses: astral-sh/setup-uv@v6
-        with:
-          enable-cache: true
-          cache-dependency-glob: "uv.lock"
-          python-version: ${{ matrix.python-version }}
-          prune-cache: false
-      - run: uv sync
-      - name: Run Codeflash Optimizer
-        working-directory: ./src/backend/base
-        continue-on-error: true
-        run: uv run codeflash
-