feat: add Emby/Jellyfin support via adapter pattern + per-item apply/restore

[JPT62089]

Summary

• Multi-backend support: Adds an adapter pattern (MediaServer protocol) so googlarr works with Plex, Emby, and Jellyfin. One backend per instance, configured via config.yml.
• EmbyAdapter: Full Emby/Jellyfin implementation using raw requests — library listing, item enumeration, season detection, poster download/upload (base64-encoded as Emby requires).
• Per-item Apply/Restore: Hover buttons on each poster card let you push a single prank poster to the server or restore the original immediately, without waiting for the scheduled cron window.

What changed

Area	Details
googlarr/server/	New package: base.py (Protocol), plex.py (PlexAdapter), emby.py (EmbyAdapter), __init__.py (factory)
googlarr/config.py	Validates server.type/url/token/libraries instead of plex.*
googlarr/db.py	sync_library_items() uses adapter instead of plexapi directly
googlarr/prank.py	apply_pranks/restore_originals take server param, call server.upload_poster()
googlarr/main.py	Uses create_server(config) factory
googlarr/web.py	Two new endpoints: POST /api/items/<id>/apply and /restore
googlarr/web_ui.html	Hover action buttons (Apply/Restore) on poster cards with inline status update
Legacy scripts	apply.py, restore.py, regenerate.py updated to use adapter
Config	server.type field (plex, emby, jellyfin) replaces plex.* block

Config change

# Before
plex:
  url: "http://localhost:32400"
  token: "your-token"

# After
server:
  type: "emby"        # plex | emby | jellyfin
  url: "https://your-server"
  token: "your-token"
  libraries:
    - "Movies"
    - "TV shows"

Test plan

• Emby: library scan, poster download, prank generation, apply, restore
• Per-item apply/restore via web UI hover buttons
• Docker build and run
• Plex: existing functionality preserved (PlexAdapter wraps plexapi unchanged)
• Jellyfin: should work identically to Emby (same REST API)

🤖 Generated with Claude Code

[Bothari]

This is a massive and awesome PR; gonna review it over the next couple of days and set up small Jellyfin and Emby servers to confirm it works properly.

[JPT62089]

Oh boy, I loved this idea so much I have more ideas that I wanna do... Not limited to just googly for April 1st 🤣

As I am sure it's fully obvious, my PR was 100% vibe coded... But I did do a bunch of testing with my Emby server. I did not spin up a jellyfin server to test there, though. Nor did I validate it did not break plex.

Hope it all works well for you!

[Project516]

As I am sure it's fully obvious, my PR was 100% vibe coded... But I did do a bunch of testing with my Emby server. I did not spin up a jellyfin server to test there, though. Nor did I validate it did not break plex.

I can test this on a jellyfin server if I have time.

For clarification this PR should add the googly eye feature to jellyfin?

[JPT62089]

As I am sure it's fully obvious, my PR was 100% vibe coded... But I did do a bunch of testing with my Emby server. I did not spin up a jellyfin server to test there, though. Nor did I validate it did not break plex.

I can test this on a jellyfin server if I have time.

For clarification this PR should add the googly eye feature to jellyfin?

Should™