fix(lint): F821 undefined 'e' in test_scm_configured; shfmt/ruff auto-fixes

- test_scm_configured.py: remove reference to exception variable `e` outside
  its except block (F821); assert message doesn't need the code value
- shfmt auto-formatted install_steps.sh (spacing in write_env call)
- ruff auto-fixed one remaining issue
- 19/19 unit tests pass; lint PASS

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

runner/harness/sso.py

@@ -455,9 +455,7 @@ def setup_gitea_oauth(provider_domain: str, parent_domain: str) -> dict:
             # Stale volume from a prior run — reset the password to the newly-generated one
             # so the API call below can authenticate. In production CI, teardown_deps removes
             # volumes so this branch is only hit in re-runs against a stale volume.
-            print(
-                f"  gitea dep: {admin_user!r} already exists — resetting password", flush=True
-            )
+            print(f"  gitea dep: {admin_user!r} already exists — resetting password", flush=True)
             lifecycle.exec_in_app(
                 provider_domain,
                 [
@@ -491,9 +489,7 @@ def setup_gitea_oauth(provider_domain: str, parent_domain: str) -> dict:
         password=admin_password,
     )
     if status not in (201, 200):
-        raise RuntimeError(
-            f"gitea OAuth2 app create failed: HTTP {status} — {resp!r}"
-        )
+        raise RuntimeError(f"gitea OAuth2 app create failed: HTTP {status} — {resp!r}")
     client_id = resp["client_id"]
     client_secret = resp["client_secret"]
     print(