ai: apply changes for #870 (1 review thread)

Addresses:
  - #3600339404 at .github/workflows/engineer-bot-followup.yml:107

Signed-off-by: peco-engineer-bot[bot] <peco-engineer-bot[bot]@users.noreply.github.com>

Author: peco-engineer-bot[bot]

.bot/prompts/engineer-followup/system.md

@@ -14,6 +14,16 @@ Your job:
      pass: `poetry run python -m pytest tests/unit/<file> -k <name>` (and the
      affected file's full set before you finish). Never weaken or skip a test to
      go green.
+       - This runner installs `--all-extras`, so the REAL `databricks-sql-kernel`
+         wheel is present. The unit suite fakes `databricks_sql_kernel` in
+         `sys.modules` (`tests/unit/test_kernel_client.py`), which shadows the
+         real wheel in a shared session — and the `@pytest.mark.realkernel`
+         routing test (`tests/unit/test_session.py::TestUseKernelRoutesThroughRealWheel`)
+         `pytest.fail`s loudly on that shadowing. So whenever you run a selection
+         BROADER than a single `-k` test — a whole file, or `tests/unit` — append
+         `-m "not realkernel"` (matching how `.github/workflows/code-coverage.yml`
+         guards the same `--all-extras` install). Skipping this produces a
+         confusing false red unrelated to your fix.
   4. End with a short summary of what changed.
 
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