feat(ui): synchronize validated SeerrNG 3.48.3 preview

[JohnCronk79]

Description

Synchronize John's fork with the accepted SeerrNG 3.48.3 preview and one-time
SeerrNG theme adoption from upstream PR snapetech#162. This is the explicitly requested
fork update after nightly closeout, not a new implementation or upstream merge.

The sync commit preserves fork main's existing history. Its entire Git tree is
exactly 07c5c2a8613405a88a53f96999528cfe1cb46cd7, matching the verified
upstream contribution head c060df0870655421dd1b40f96d3d93fb564c9658.
The separate sync head may be deleted after squash merge; the integration
branch used by upstream PR162 must remain intact. Other open PRs are untouched.

AI Disclosure: I used OpenAI Codex extensively to assist with code changes, merge analysis, validation, and submission. I directed each visual decision and personally reviewed the affected pages in the running preview before approving this pull request.

That statement refers to the earlier accepted preview and design decisions.
John expressly authorized this exact-source fork synchronization and automatic
relevant PR follow-up. No new whole-site visual review is claimed.

How Has This Been Tested?

• Upstream PR162 current head: all 15 applicable checks passed, including
  Cypress, Unit Tests, builds, lint, translations and security. Four main-only
  publishing/deployment checks were intentionally skipped.
• Initial amended-source engine: 4,006 passed, zero failed, four conditional
  PostgreSQL skips, 557 files and 4,010 cases in 332.790 seconds, at initial
  tree f08788727b07ab4e48533f3674d1c36222c72171.
• Subsequent changes affect only two test files: a Cypress account-palette
  setup and one removed unused native-test helper. All four affected native
  tests passed; application bytes are unchanged. GitHub validated current head.
• Normal attribution, formatting, lint-staged and commit-message hooks passed.
  Exact sync/contribution tree equality and clean working state were verified
  after those hooks. A first commit-message attempt was rejected for line width;
  the corrected message passed without disabling hooks.
• John waived another local production compile for the theme amendment. No
  local recompile, live-provider write, NAS deployment or production migration
  was performed during fork synchronization.

Screenshots / Logs (if applicable)

The accepted previews remain preserved. Source verification is on
snapetech#162. Private nightly records retain
the source-bound receipts and exact cleanup exceptions, without runtime secrets.

Release Notes

• I added a release-note fragment under release-notes/.
• This change is internal-only and does not need a user-facing release note.
• The fragment includes audience, area, action, and breaking-change status.
• I previewed the release text with pnpm release-notes:preview.

Existing verified contribution fragments are preserved verbatim in the sync.

Checklist:

• I have read and followed the contribution guidelines.
• Disclosed any use of AI (see our policy)
• I have updated the documentation accordingly.
• All new and existing tests passed.
• Successful build pnpm build
• Translation keys pnpm i18n:extract
• Database migration (if required)

Unchecked boxes preserve the documented conditional PostgreSQL skips and local
compile waiver. GitHub's separate current-source build and test checks passed.
Migration verification used disposable fixtures, not a live production database.