test(harness): make formatClockTime tests locale independent

[memosr]

Primary change type

• Tests

Problem and motivation

pnpm test fails on any machine whose system locale is not English:

FAIL  web/src/lib/session-record-view.test.ts > formatClockTime > adds the date for a turn from another day
AssertionError: expected '1 Tem, 13:00' to match /Jul/

CI runs in an English locale, so this is green upstream and red for contributors elsewhere. I hit it on a fresh clone of main, before changing anything, on macOS with a tr-TR system locale.

formatClockTime calls toLocaleDateString([], ...) deliberately, so a timestamp reads in the user's own locale. That is correct for a user-facing string. The test was the over-specified side: matching /Jul/ pins an English month abbreviation, while the behavior it means to assert is "a date is added when the turn is from another day".

Summary and scope

Assert the shape instead of the wording. The same instant is formatted twice, once with now at that instant and once three days later, and the dated form is asserted to be the same-day form with a date and ", " in front.

Out of scope: no source file is touched, and no other locale-dependent assertion elsewhere in the repo is changed.

Related work

Related issue or discussion: N/A — direct PR, focused test fix under the direct-PR policy.

Validation

pnpm --filter @sapiom/harness test        — pass (2095/2095)
pnpm build                                — pass
pnpm typecheck                            — pass
pnpm lint                                 — pass (0 errors)

The two tests were additionally run under de-DE, ja-JP, tr-TR and en-GB, each in Asia/Tokyo, America/Los_Angeles and UTC.

Tests and documentation

Tests: the two formatClockTime assertions are rewritten. Documentation: N/A, no user-facing behavior changed.

Compatibility and release impact

• Breaking or externally visible changes: None. Test-only.
• Changeset: An empty changeset is included, since no published behavior changes.

Security

• I have not included secrets, credentials, private data, or unsanitized logs.
• This pull request does not publicly disclose a suspected vulnerability.

AI assistance

• I used AI assistance and have described it below.

I used Claude (Claude Code and the Claude app). The failure was found by running pnpm test on a clean clone. I decided that the test rather than the source was wrong, and directed the change to assert the same-day/other-day relationship rather than an English month name. Claude wrote the two rewritten assertions and ran them across the locale and timezone matrix listed above. I reviewed the diff line by line and re-ran the full package suite myself.

Checklist

• I read CONTRIBUTING.md, and this contribution follows the direct-PR or issue-first policy.
• This pull request addresses one focused problem and contains no unrelated cleanup.
• I added or updated tests, or explained above why tests are not applicable.
• I ran the relevant build, typecheck, lint, and test commands, or explained any N/A checks above.
• I updated documentation for user-facing changes, or marked it N/A above.
• I added a Changeset for a published-package change, or explained why it is not applicable.
• I can explain and maintain every submitted change, including any AI-assisted work.