test(flash): build the turn-index runner without provider credentials

[basil-k-aji-dev]

Closes #31.

Problem

tests/unit/agents/flash/test_turn_index_snapshot.py fails 4 of its 5 tests without GOOGLE_API_KEY, contrary to the deterministic-suite contract in CONTRIBUTING.md:

$ uv run pytest -q tests/unit/agents/flash/test_turn_index_snapshot.py
4 failed, 1 passed
E   pydantic_core._pydantic_core.ValidationError: 1 validation error for ChatGoogleGenerativeAI
E     Value error, API key required for Gemini Developer API.

FlashRunner.__init__ constructs a VisualStepSummarizer, whose constructor resolves a real model client. The _runner helper already intends to discard it:

runner = FlashRunner(mock_context, goal="Open Wi-Fi and Display")
runner.summarizer = None   # never reached -- the line above raised

but that assignment runs after construction, so it never takes effect.

Change

Patch VisualStepSummarizer for the construction itself, in the with block that already patches get_driver:

with (
    patch("artemis.controllers.unified_controller.get_driver"),
    patch("artemis.agents.flash.runner.VisualStepSummarizer"),
):
    runner = FlashRunner(mock_context, goal="Open Wi-Fi and Display")
runner.summarizer = None

Patching the whole class is safe here precisely because the helper was already throwing the instance away: these tests assert index resolution across a turn and never summarize anything, so nothing under test is mocked out.

Test-only; no production code is touched.

Relationship to #41

#41 covers the same root cause in four other Flash modules and I've sent a fix for it separately (#86). That one introduces a stub_summarizer_model_factories fixture in tests/unit/agents/conftest.py, which would also cover this file once merged.

I kept this PR self-contained instead of depending on it, so the two can land in either order or independently. If #86 lands first and you'd rather this file used the shared fixture too, say so and I'll rebase it onto that.

Verification

Command	main	this branch
uv run pytest -q tests/unit/agents/flash/test_turn_index_snapshot.py	4 failed, 1 passed	5 passed
uv run ruff check tests/	—	All checks passed
uv run ruff format --check on the touched file	—	already formatted

Run with GOOGLE_API_KEY, GEMINI_API_KEY and OPENAI_API_KEY all unset.

make typecheck could not be run in my environment — the pyright wheel downloads a Node runtime on first use and my sandbox blocks it. The touched file is not in pyright-core.json.

[basil-k-aji-dev]

Closing as a duplicate. #32 by @Fire162 already covers issue #31 and was opened first — that one should get the review, not this.

My mistake: I didn't check the open PR queue for an existing claim before sending this. Sorry for the noise.