v2.1.1 - Configurable Coming Soon look-ahead

What's changed

• Adds a configurable Coming Soon look-ahead window via the new
  coming_soon_lookahead_days add-on option (env
  COMING_SOON_LOOKAHEAD_DAYS, frontend key comingSoonLookaheadDays).
  Range is 1–365 days; the default remains 90 so existing installs
  keep their current behaviour (closes #85, PR #86).
• Radarr eligibility now considers both digitalRelease and
  physicalRelease. When both are present, the earliest qualifying date
  inside the look-ahead window is selected.
• inCinemas is intentionally still excluded as a release-date
  fallback, so theatrical-only entries do not appear in Coming Soon.
• The configured movie/show counts remain an upper bound — the look-ahead
  only changes how far forward we look for eligible items.
• /api/config, the setup form, the /api/coming-soon direct-fetch path,
  and Radarr/Sonarr mappers all honour the new look-ahead window so the
  picked release date, countdown, and releaseLabel stay consistent.

Tests

• cd server && node --test test/ — 139 passed, 0 failed, including
  new cases for physicalRelease eligibility, earliest-of-digital/physical
  selection, falling back to digitalRelease when physical is outside
  the window, rejecting inCinemas-only items, the hasFile filter, and
  lookaheadDays default + clamping.

Packages

• Add-on package version is 2.1.1.
• The addon-v2.1.1 tag has been pushed to trigger the multi-arch GHCR
  build that publishes:
  • ghcr.io/rusty4444/plex-now-showing-amd64:2.1.1 (and :latest)
  • ghcr.io/rusty4444/plex-now-showing-aarch64:2.1.1 (and :latest)
  • ghcr.io/rusty4444/plex-now-showing-armv7:2.1.1 (and :latest)
  • ghcr.io/rusty4444/plex-now-showing-armhf:2.1.1 (and :latest)
  • ghcr.io/rusty4444/plex-now-showing-i386:2.1.1 (and :latest)
• Supervisor pulls the matching 2.1.1 Docker tag for each arch from
  addons/plex-now-showing/config.yaml's version field.