feat(http): enable gzip + brotli decompression for reqwest clients (#704)

* feat(http): enable gzip + brotli decompression for reqwest clients

All Rust-side HTTP clients now advertise Accept-Encoding and transparently
decode compressed responses. reqwest auto-decompresses by default once the
features are enabled, so this is a pure dependency-feature change with no
call-site edits.

Added to all five reqwest declarations across the Cargo workspace
(top psysonic crate + psysonic-audio / -analysis / -integration / -syncfs).
The real wire savings land on JSON payloads — Navidrome native /api,
Bandsintown, Radio-Browser, Last.fm — measured at roughly -76% to -93% on
earlier curl tests. Crates that only fetch already-compressed audio bytes
get the features too for consistency: reqwest just advertises the header
there, so there's no runtime cost when the server returns data as-is.

Cargo.lock grows additively (async-compression + compression codecs); no
other crates moved.

* docs(changelog): add entry for HTTP gzip + brotli (#704)

src-tauri/crates/psysonic-integration/Cargo.toml

@@ -12,7 +12,7 @@ tauri = { version = "2" }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 tokio = { version = "1", features = ["rt", "time", "sync"] }
-reqwest = { version = "0.13", default-features = false, features = ["stream", "json", "rustls", "blocking"] }
+reqwest = { version = "0.13", default-features = false, features = ["stream", "json", "rustls", "blocking", "gzip", "brotli"] }
 futures-util = "0.3"
 discord-rich-presence = "1.1"
 url = "2"