fix: declare frontend date dependencies and expiry contract

[Jacky-Pham]

Host and Examiner import Luxon directly without declaring it, causing four missing-module/type errors. Add Luxon 3.7.2 and @types/luxon 3.7.1 to both apps, matching Base's existing locked versions. No existing dependency resolution changes.

The now-available Luxon types expose the shared registration expiry-date mismatch: the API serializes an ISO string, while the frontend declared a Date. Correct that field to string so Host renewal calculations use the actual response contract.

Add seven passing controls covering rendered Pacific filing-history dates and document-upload timestamp comparisons. These checks passed before the dependency change; this PR does not claim a reproduced production date-rendering failure.

Validation:

• Frozen installs, 35 Host tests, 28 Examiner tests, and both apps' local lint passed (Examiner retains two existing line-length warnings).
• Combined CI at 71d8a5ab925fb0b439b44381b1f07aeda99ec777: all five apps passed lint, 1,122 tests, and builds.
• Ordinary PR checks at 6ebcd0854efba418e620f09bb6423db6d8a5969f passed: Base, Host, and Examiner.
• All five apps were freshly checked with local Base under both existing strict profiles, removing exactly four diagnostics with none added. The combined repair branch retains 55 default-profile or 40 configured-profile diagnostics; the profiles overlap and are not additive. The review stack retains 332 default-profile or 313 configured-profile diagnostics because other shared-layer repairs are separate drafts.

Stacked on #1833. Draft for review; no deployment.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud