feat: add multi.kagane

[m1000-spicy]

No description provided.

[m1000-spicy]

• source.json: reset version to 1, lower contentRating to Suggestive,
  and drop the redundant listings block (duplicated the sort filter)
• filters.json: remove redundant ids on the format filter
• settings.json: drop redundant titles; add a Languages multi-select
  feeding content_lang so the source isn't locked to English
• helpers: rebuild the search body with serde_json and delete the
  hand-rolled escape_json helper
• home: mirror the site with Popular Today / Recently Added scrollers

[kkantan]

it would be nice to have supportsTagSearch implemented. author search is also supported on the website. another optional thing to have would be the AlternateCoverProvider trait, but that is definitely not necessary.

[m1000-spicy]

it would be nice to have supportsTagSearch implemented. author search is also supported on the website. another optional thing to have would be the AlternateCoverProvider trait, but that is definitely not necessary.

Implemented. I added a Genre multi-select with all 66 genres and their UUIDs (with exclude support), and wired the search body to the API's real shape — genres: { values, exclude, match_all: true }. config.supportsTagSearch is on, so tapping a genre on a series page runs a genre search too.

I dug into this one but couldn't get it working cleanly. The search endpoint only filters authors via a UUID-keyed staff field, and there's no author-lookup endpoint to convert a typed name into a UUID — so it can't work the way MangaDex's author search does. I've left it out for now; happy to add it if you know of an endpoint I missed.

Skipped AlternateCoverProvider for now since it's not necessary