feat(live-tv): browse channel guide and play catch-up from the player

[bilipp]

Summary

Adds catch-up support to the in-player live-TV experience. The channel switcher (left press on the Siri remote during playback) now has a third Liquid Glass column — the Guide of the focused channel. Channels that advertise an archive are flagged, and from their guide the viewer can pick an already-aired programme to replay via catch-up, addressing the issue's ask to "go back and watch programs that already aired."

Implementation

• Third "Guide" column in TVChannelBrowserOverlay: it follows channel focus (debounced like the category/channel columns), shows the channel's programmes oldest-first, marks the live programme, and renders a catch-up affordance on past entries. Categories / Channels / Guide are each their own focusSection, so the remote hops between them.
• Catch-up highlighting: channel rows that report tvArchive > 0 get a clock.arrow.circlepath badge so the viewer knows a replay archive is available before stepping into the guide.
• Playback: selecting the live programme plays the channel live; a past programme starts catch-up; an upcoming one is a no-op. Catch-up is modelled as a new PlayableMedia.catchup(...) — kind: .vod (seekable archive, no live banner, channel surfing disabled) with the channel's .live content ref (so no watch-progress is written, matching existing live behaviour).
• EPG fetching rework: the local store already retains past programmes (XMLTV sync is wipe-and-replace with no time filtering), so no sync change was needed. Added TVPlayerContent.guideListings(channelId:archiveDays:), which reaches back over the archive window for catch-up channels (the existing epgListings only returned end > now). The index-served channelId + end query keeps it to a small slice of the guide.
• Catch-up URL fix: XtreamClient.buildCatchupURL was previously unused and built a non-standard path (unix timestamp + seconds). Rewrote it to the standard Xtream timeshift format …/timeshift/user/pass/{durationMinutes}/{Y-m-d:H-i}/{streamId}.{ext}.

Testing

• Acceptance criteria met
• Tests pass (PlayableMediaTests, XtreamClientURLTests — iOS 17 Pro sim, TEST SUCCEEDED)
• tvOS build compiles (Apple TV 4K, tvOS 26.5 — BUILD SUCCEEDED)
• SwiftLint / SwiftFormat clean (pre-commit hooks passed)
• Tests added — catch-up URL format + PlayableMedia.catchup (archive / non-archive / m3u cases). The guide column and focus flow are tvOS-only UI (tests run on iOS sim), so they were verified by build only.

Platforms

• tvOS

Related

Closes #25