Add cbox test command for running visual tests locally in Linux container

ID	ISSUE-366
Status	done
Priority	p2
Milestone	m1-ft-analytics-analyst-pilot
Owner	head-of-engineering

Problem

Visual regression tests for chart and render output frequently pass on macOS developer machines but fail in CI’s Linux container due to differences in font rendering, system libraries, and SVG rasterization. Developers have no local way to reproduce CI’s exact rendering environment, so they iterate blindly — push, wait for CI, read diffs, guess at fixes, push again. This cycle wastes significant time for any change touching chart rendering. A first-class cbox test command that runs visual tests inside the same Linux container used by CI would let developers catch rendering discrepancies before opening a PR.

Context

cbox visual-test command runs the expected test subset with deterministic output.
Local container workflow matches CI dependencies, fonts, and rendering behavior.
Developers can quickly reproduce and debug visual diffs before opening PRs.

Possible Solutions

Plan

Define command UX (cbox subcommand name, args, and output conventions).
Implement container invocation and volume mounts for fixtures/baselines.
Add docs with examples for run, update-baseline, and debug flows.
Validate command on clean checkout and common dev host setups.
Attach logs/screenshots to issue showing parity with CI execution.

Implementation Progress

Completion notes

Full cbox test command implemented at libs/cbox/cbox/cli.py:2786 with flags: --update, -k, --shell, --python, --repo-path.
Container build_test_command at libs/cbox/cbox/container.py:454 mounts repo, overrides entrypoint, supports worktree git metadata.
7 unit tests in libs/cbox/test_test_command.py — all passing.
No spillover identified; feature is self-contained.
GitHub issue: https://github.com/fivetran/dataface/issues/366

Review Feedback

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