Keep dashboard identity, requests and recently added media reliable

[mayvqt]

Seerr history and quotas now require an explicitly linked account, and integration caches and login sessions are separated when the media server changes. Recently added TV episodes are consolidated into one card per show, ordered by the newest episode and linked to the show.

• Keep media-only setups usable with optional public links and clear empty, partial, stale, and unavailable states.
• Preserve complete cache entries during failures, coalesce concurrent refreshes, and bound admin service checks.
• Correct TV season eligibility, request conflicts, calendar release dates, playback errors, branding, and background refresh focus/CSRF handling.
• Group recent episodes by stable series ID while preserving media-server Latest preferences. Expand the fetched history only when it can affect the final list; keep same-name shows and movies distinct. Version the widget cache so old episode cards cannot return after an outage.
• Show the full brand, sign-out control and navigation on mobile. Fix the recently added rail's mobile grid rule, which collapsed its first two cards when more titles were present.

Validation: affected Go race tests and vet passed; browser JavaScript lint/tests passed for the earlier dashboard changes. Synthetic desktop and mobile browser checks covered TV season requests, saved branding with blank public links, and unlinked-account permissions. The new 230-episode import fixture produced 12 distinct destinations in newest-addition order; card layout and keyboard navigation passed at widths 1440, 390 and 320 with no console errors or page/card overflow. Earlier header checks also covered 768 and 979. Local Go 1.27.1 and Node 26 checks supplement CI with the repository's specified tool versions. The final CI gate passed on fd3f0ea4dcf0df8748fc7df0d40c8f3eafbec4a3, including tests, race detection, vet, static analysis, dependency vulnerability scanning, browser JavaScript checks, the server build and Docker.

No live providers were modified. Recent-media traversal has a ten-second overall deadline, a 2 MiB response limit and a 4,096-row ceiling; incomplete results return an error instead of replacing a complete cache. Episodes without a supplied series ID remain separate.