fix(python): always use fake token in E2E tests to prevent hang

[brettcannon]

Problem

When running Python E2E tests locally (outside CI), they hang indefinitely on any test that sends a message via send_and_wait().

Root Cause

The E2E test harness overrides XDG_CONFIG_HOME to an isolated temp directory for test isolation. When not in CI, github_token was None, so the CLI defaulted to use_logged_in_user=True — but found no credentials in the empty temp dir.

The CLI logged Error: Session was not created with authentication info or custom provider but never emitted a session.error event back to the SDK, so send_and_wait() blocked forever waiting for a session.idle that would never come.

Fix

Always pass github_token="fake-token-for-e2e-tests" in the test harness and in the one test that creates its own client. Since E2E tests use a replaying proxy with canned responses, real auth is never needed.

Verification

All 74 Python E2E tests pass (2 pre-existing skips for known unrelated issues).

[Copilot]

Pull request overview

Fixes local Python E2E test hangs by ensuring the Copilot CLI never attempts interactive/credential-based auth when the harness points XDG_CONFIG_HOME at an empty temp directory.

Changes:

• Always pass github_token="fake-token-for-e2e-tests" when constructing the shared Python E2E CopilotClient.
• Update the one test that creates its own CopilotClient to also always pass the fake token.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
python/e2e/testharness/context.py	Makes the shared E2E client always use a fake auth token to prevent CLI auto-login behavior from hanging tests locally.
python/e2e/test_session.py	Ensures the test-created “new client” uses the same fake token behavior as the harness client.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.