add http-json, rss, and media data source adapters

http-json: generic HTTP+JSON polling adapter, converts serde_json to domain Value. 4 tests.
rss: XML RSS feed parser, extracts items into Value array. 1 test.
media: Navidrome/Subsonic getNowPlaying adapter. 2 tests with fake server.

Cargo.toml

@@ -11,6 +11,9 @@ members = [
     "crates/adapters/display-terminal",
     "crates/adapters/config-sqlite",
     "crates/adapters/http-api",
+    "crates/adapters/http-json",
+    "crates/adapters/rss",
+    "crates/adapters/media",
     "crates/bootstrap",
     "crates/client-desktop",
 ]
@@ -39,3 +42,4 @@ sqlx = { version = "0.8", features = ["runtime-tokio-rustls", "sqlite"] }
 postcard = { version = "1.1", default-features = false, features = ["alloc"] }
 tokio = { version = "1.0", features = ["macros", "rt", "rt-multi-thread", "net", "sync", "time", "io-util"] }
 tower = "0.5"
+reqwest = { version = "0.12", features = ["json"] }