First commit toward torrent and usenet download sources. Prowlarr is
the indexer manager component of the *arr stack — it exposes Usenet
and torrent indexers behind a single Newznab-style API so SoulSync
doesn't have to integrate each indexer individually. This commit
wires up Prowlarr as a search-only source; the torrent and usenet
download client adapters land in the next commits and plug into
this search surface.
- core/prowlarr_client.py: sync-backed async client. is_configured,
check_connection, get_indexers, search by Newznab category. Music
category constants (3000 all / 3010 MP3 / 3040 lossless / etc.).
- core/connection_test.py: 'prowlarr' branch hits /api/v1/system/status
for the Test Connection button.
- web_server.py: GET /api/prowlarr/indexers returns the live indexer
list (id, name, protocol, enabled, privacy). Settings POST allow-list
now accepts 'prowlarr' so saved config persists.
- config/settings.py: prowlarr.{url, api_key, indexer_ids} defaults
plus prowlarr.api_key in the encrypted-at-rest secrets list.
- webui/index.html: new "Indexers & Downloaders" tab on Settings with
the Prowlarr panel (URL, API key, Test, Refresh Indexer List,
optional indexer-ID allowlist).
- webui/static/settings.js: load/save wiring, testProwlarrConnection,
loadProwlarrIndexers (HTML-escapes user-supplied indexer names).
- webui/static/helper.js: WHATS_NEW 2.6.0 unreleased block plus a
curated VERSION_MODAL_SECTIONS entry.