fix(ci): integration workflow installs requirements.txt, not 'pip install -e .'

The repo is not a pip package (no setup.py/pyproject.toml; it runs via
PYTHONPATH, as ci.yaml documents), so integration.yaml's 'pip install -e .'
always errored ('does not appear to be a Python project') whenever the Mac M4
integration job actually ran. #157 triggered that job (it adds an integration
test), exposing the pre-existing break. Install runtime deps from
requirements.txt instead; the suite already runs with PYTHONPATH=.:sdks/python.

Co-authored-by: FluffyAIcode <FluffyAIcode@users.noreply.github.com>

Author: cursoragent

.github/workflows/integration.yaml

@@ -85,7 +85,11 @@ jobs:
           # The runner is expected to have a long-lived venv.
           # If a per-run venv is preferred, swap to ``python3 -m venv .venv``.
           python3 -m pip install --upgrade pip
-          python3 -m pip install -e .
+          # The repo runs via PYTHONPATH (see ci.yaml) — it is NOT a pip package
+          # (no setup.py/pyproject.toml), so install runtime deps from
+          # requirements.txt rather than an editable `-e .` (which errors with
+          # "does not appear to be a Python project").
+          python3 -m pip install -r requirements.txt
           python3 -m pip install pytest pytest-asyncio pytest-timeout coverage
 
       - name: Run integration suite