fix(release-watch): drop upcoming and non-streamable albums

`/favorite/getNewReleases` includes albums whose stream availability is
still in the future, so they appear in the Release Watch grid even
though `get_album` 404s as soon as the user clicks them. Same shape for
regional restrictions and label takedowns surfaced via `streamable=false`.

Add `release_date_stream` and `streamable` to the Album struct (both
optional with serde defaults so existing call sites stay happy) and
filter the response inside `v2_get_release_watch` after the artist
blacklist pass: skip any album marked `streamable=false` or whose
`release_date_stream` is strictly greater than today (UTC). The total
count gets adjusted alongside so pagination math stays consistent.

cc

crates/qbz-models/src/types.rs

@@ -251,6 +251,14 @@ pub struct Album {
     #[serde(default)]
     pub image: ImageSet,
     pub release_date_original: Option<String>,
+    /// Date the album becomes available for streaming (ISO YYYY-MM-DD).
+    /// When in the future, the album is upcoming and cannot be fetched
+    /// via `get_album` yet — Release Watch uses this to gate clicks.
+    pub release_date_stream: Option<String>,
+    /// Whether the album is currently streamable. False for upcoming
+    /// releases, regional restrictions, or label takedowns.
+    #[serde(default)]
+    pub streamable: Option<bool>,
     pub label: Option<Label>,
     pub genre: Option<Genre>,
     pub tracks_count: Option<u32>,