feat: add Kick, Dailymotion, and PeerTube backends to alert plugin

Kick (kk) searches channels and livestreams via public search API.
Dailymotion (dm) queries video API sorted by recent. PeerTube (pt)
searches across 4 federated instances with per-instance timeout.
All routed through SOCKS5 proxy via _urlopen.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/USAGE.md

@@ -689,13 +689,16 @@ Platforms searched:
 - **Mastodon** (`ft`) -- Public hashtag timeline across 4 instances (no auth required)
 - **DuckDuckGo** (`dg`) -- HTML lite search endpoint via SOCKS5 proxy (no auth required)
 - **Google News** (`gn`) -- Public RSS feed via SOCKS5 proxy (no auth required)
+- **Kick** (`kk`) -- Public search API: channels and livestreams (no auth required)
+- **Dailymotion** (`dm`) -- Public video API, sorted by recent (no auth required)
+- **PeerTube** (`pt`) -- Federated video search across 4 instances (no auth required)
 
 Polling and announcements:
 
 - Alerts are polled every 5 minutes by default
 - On `add`, existing results are recorded without announcing (prevents flood)
 - New results announced as `[name/<tag>] Title -- URL` where tag is `yt`, `tw`,
-  `sx`, `rd`, `ft`, `dg`, or `gn`
+  `sx`, `rd`, `ft`, `dg`, `gn`, `kk`, `dm`, or `pt`
 - Titles are truncated to 80 characters
 - Each platform maintains its own seen list (capped at 200 per platform)
 - 5 consecutive errors doubles the poll interval (max 1 hour)