fix(xtream): detect HTTP portals during explicit connection tests (#1588)

CLAUDE.md

@@ -809,6 +809,18 @@ categories by provider ID and type. See `docs/architecture/category-management.m
 
 ### Key Features
 
+#### Xtream Connection Test
+
+Add/Edit source Test HTTPS and HTTP discloses plaintext credential use before
+the click and can replace an unavailable HTTPS base with a
+verified active HTTP base in the form. Only initial refused-port or TLS
+wrong-version evidence permits the same-host attempt; HTTP errors, certificate
+failures and redirect failures do not. Add/Save persists `serverUrl`, and the
+routed session observes the metadata change. Passive checks never change the
+protocol. Separate XMLTV and already-issued media/download URLs stay independent.
+Contract: `docs/architecture/xtream-portal-compatibility.md`
+("Explicit protocol discovery").
+
 #### Xtream Live Auto Format
 
 The routed Xtream live host supplies `liveAutoTsUrl` only for Auto with explicit