QA Promotion: Local-Timezone Timestamps, Safer ZIP Batch Previews, and Rules/Tags Cleanup

A batch promotion advancing the current development build into the QA environment for testing. It bundles three changes to the Mail app: timestamps now display in each viewer's own local time zone instead of fixed US Central time, a fix that stops ZIP batch archives from silently downloading when opening Edit Batch, and a cleanup that hides an unfinished rule auto-apply workflow and removes unsupported tag/rule API calls.

Three distinct issues motivated this batch:

• Timezone display: every timestamp was hardcoded to US Central time, so users outside that zone saw times that did not match their own clock.
• Silent ZIP downloads: opening Edit Batch on a ZIP-backed batch could auto-download the raw archive to the user's machine, because the preview pane was handing a .zip URL to a PDF viewer that browsers cannot render inline.
• Contract drift (BUG-017): the frontend still carried calls for rule and tag management endpoints (auto-apply, activate, tag create/update) that the backend does not currently expose, plus an auto-apply UI for a workflow product had not re-enabled.

• Timestamps across the Mail app now render in the viewer's local device time zone (same MM/DD/YYYY visual format), so a user in Mumbai and a user in Chicago each see the correct local wall-clock time for the same moment.
• Opening Edit Batch on a ZIP batch no longer triggers an unexpected file download; the preview shows a loader while extraction runs and a clear placeholder for archives.
• The unfinished "Auto Apply Rules" buttons no longer appear in Admin Hub, and the app no longer calls tag/rule endpoints that would error, reducing confusing failures.

Promotion of dev into qa, bundling three feature branches (Mail app + shared UI package):

• Local-timezone timestamps (#1046): packages/ui/src/utils/format-date.ts drops the America/Chicago TZDate pin; a new normalizeTimestampString helper treats zone-less datetimes as UTC (per backend contract) and pins date-only strings to local midnight to avoid day-rollback in negative-offset zones, then date-fns format() renders in local time. Removes the now-unused direct @date-fns/tz dependency from packages/ui/package.json.
• Silent ZIP download fix (#1045): adds a strict hasZipExtension helper in fileValidation.ts; useEditBatchZipProcessing only ever surfaces extracted blob entries (never the raw .zip URL); FilePreview routes archives to a download-card and shows a preparing loader before the empty state; pdf-viewer/index.tsx refuses to mount the iframe for .zip URLs as a defense-in-depth guard; AddBatchModal reports edit-mode loading state.
• Friday 12th June fixes (#1044): adds a rulesAutoApply feature flag (default false) gating all Auto Apply Rules buttons/modals in RulesTab.tsx and the rules page; removes ~1,000 lines of unsupported frontend wrappers for rule management/test/execute/templates/analytics endpoints and standalone tag create/update (read-only getTags retained).

Low-to-moderate. The timezone change touches a shared helper used by every timestamp across admin, mail, and vendor apps, so any regression would be broad; mitigated because the visual format is unchanged and only the rendered offset differs. The ZIP and rules changes are net-removals or additive guards that reduce surface area. Tag/rule mutation removal is safe only if no remaining code path calls those wrappers (PR notes a source check found no references). Watch for hydration warnings from server/client timezone mismatch.

• Verify timestamps render in your local time zone on the qa deploy from a non-Central time zone; confirm visual format stays MM/DD/YYYY and date-only fields do not shift by a day; watch the browser console for hydration warnings.
• Open Edit Batch on a ZIP-backed batch and confirm NO automatic download occurs; confirm a loader shows during extraction and extracted PDFs preview correctly.
• Confirm the "Auto Apply Rules" button is hidden in Admin Hub Rules (single and bulk-selection views) while the flag is off.
• Smoke-test document tag creation through the upload/update flow (via new_tags) and confirm rule list/create/update/delete still work.