test(cli): cover formatLintFindings and normalizeErrorMessage

[calcarazgre646]

What

Test coverage for two pure cli helpers that had none:

• utils/lintFormat.ts (formatLintFindings): the shared console formatter behind lint, render, preview, and publish. 12 tests covering the file-label threshold (single vs multiple files), showElementId, info suppression by default and inclusion under verbose, input-order default vs errorsFirst grouping (info last), the indented Fix: hint line, and the showSummary footer including the verbose-only info count.
• utils/errorMessage.ts (normalizeErrorMessage): the fallback cascade used by render error paths. 10 tests covering Error instances, strings, objects with and without a string message, the JSON fallback, the key-list fallback for cyclic objects, the String() last resort for an object that throws from both JSON.stringify and Object.keys (Proxy with a throwing ownKeys trap), and the null/undefined/primitive paths.

No source changes.

Notes

• Fixtures build the full ProjectLintResult shape (per-file counts plus totals) rather than only the fields the formatter happens to read, so they stay valid if the formatter starts consuming more of the result.
• Output assertions target plain substrings. ui/colors.ts disables ANSI when stdout is not a TTY, which holds for vitest workers locally and in CI.
• Each assertion group was checked against a mutated implementation before committing (disabling errorsFirst grouping and removing the message-property preference both produce failures).

Suite: 710/710 cli.