Clear the 0.3 SwiftLint trailing-comma baseline

[coenttb]

Summary

• remove the 29 trailing commas rejected by repository-pinned SwiftLint 0.62.2
• limit the relative diff to the seven affected test files
• leave source behavior, tests, and lint/format configuration unchanged

Closes #11

Verification

• SwiftLint 0.62.2 positive control: 29 serious trailing_comma findings across 27 files before the change
• SwiftLint 0.62.2 after the change: 0 findings across the same 27 files
• workspace package build --fresh on current release/0.3: passed with Swift 6.4
• workspace package test --fresh on current release/0.3: all 130 tests passed
• swift-format 602.0.0 lint: exits 0, while the existing formatter configuration reports inverse TrailingComma warnings at these lines plus warnings already present on the maintenance base
• full CI on exact head: pending

The formatter-policy conflict is unchanged because #11 expressly requires the legacy SwiftLint baseline to be cleared without configuration changes.