fix: align column test fixtures

[caio-pizzol]

Fixes a stale SD-2629 layout-engine Bun test expectation left after the explicit-column no-scale geometry flip.

Root cause:

• Current column geometry preserves authored explicit widths. For the test case, the second column starts at 50 + 100 + 48 = 198.
• The test still computed the old scaled-width position and expected 198.8, so unit-tests (other-packages) failed in the Bun test step.

What changed:

• Updated the layout-engine test to expect the authored-width column position.

Context:

• The earlier clickToPosition and columnRegions fixture fixes are already present on current main, so this branch now only carries the remaining layout-engine expectation.

Checks:

• pnpm install --frozen-lockfile --ignore-scripts
• pnpm exec prettier --check packages/layout-engine/layout-engine/src/index.test.ts
• git diff --check
• Lefthook pre-commit: check-dts-shadows, format, lint

Local unit tests were not run because this repo forbids local unit test runs. CI should run the affected Bun path.

[linear-code]

SD-2629

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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