Resolve the formatDate name collision in apps/web

[selfcontained]

What

apps/web exported three different functions named formatDate, each with different behavior:

Module	Behavior
components/app/activity-chart-utils.ts	one-line delegation to formatShortDate
components/app/release-utils.ts	one-line delegation to formatShortDateTime
components/app/jobs-helpers.tsx	null guard + invalid-date guard, then formatDateTime

Same name, three semantics. Reading formatDate(x) at a call site told you nothing about what you'd get, and the import path was the only disambiguator.

• Deleted the two pure delegations. Their five call sites now import formatShortDate / formatShortDateTime from @/lib/format directly (activity-pane.tsx, activity-chart-utils.ts internal use, release-admin.tsx, updates-section.tsx ×2).
• Renamed the jobs-helpers one to formatJobDateTime and left its body untouched. Its three call sites (jobs-history-tab.tsx ×2, jobs-detail-pane.tsx) and its test block were updated.

Why this is tech debt

The two deleted wrappers added an indirection layer with zero behavior of their own, and their only effect was to make a widely-used name mean three different things in one app. Net -9 lines of indirection, and formatDate no longer resolves ambiguously anywhere in the repo.

No behavior change. Every call site resolves to the exact same underlying formatter it did before.

Deliberate exclusions

• jobs-helpers's guards were kept, not inlined. All three of its call sites do in fact pass a non-null value today (run.startedAt is typed string; run.completedAt and job.nextRun are truthiness-guarded at the call site), so the "Not scheduled" branch is unreachable from current callers. But the "Unknown" invalid-date branch is a real fallback and the fallback strings are job-domain wording — inlining them at three sites would have been strictly worse than one well-named helper. Renaming resolves the collision without touching behavior.
• formatDateTime / formatShortDateTime / formatShortDate in @/lib/format are untouched — they are the canonical formatters and are not duplicates of each other.
• Not swept:service-resources-format.ts and other same-shaped-but-different display helpers noted in the backlog (shortModelName, statusIcon, TabButton collisions) — those are genuinely different functions that happen to share a name, and are tracked as their own backlog item.

Validation

• pnpm run check ✅
• pnpm run finalize:web ✅
• apps/web vitest: 776 passed / 58 files ✅
• pnpm run test:e2e: 179 passed / 12 skipped ✅ (covers the jobs pane and the settings/updates section, which render two of the changed call sites)
• Server vitest skipped — no backend files changed.

Queued next

Backlog index 0: the dead design-system surface policy call (ui/sheet.tsx, unused shadcn wrappers, five unused lib/glass.ts tokens) — deliberately its own run because it's a keep-or-delete policy decision, not a mechanical fix.