feat: feed UI, in-app player, offline mode, settings

Adds an end-to-end integration test that runs the real pipeline against
live YouTube Atom feeds, verifying the merged feed is newest-first
across channels.

src-tauri/tests/pipeline.rs

@@ -0,0 +1,68 @@
+//! End-to-end check of the real pipeline: Takeout CSV -> live Atom feeds ->
+//! SQLite -> feed query. Hits the network, so it is ignored by default.
+//! Run with: cargo test --test pipeline -- --ignored --nocapture
+
+use flighttube_lib::{db::Db, feed, models::FeedFilter, takeout};
+
+const CSV: &str = include_str!("fixtures/subscriptions.csv");
+
+#[tokio::test]
+#[ignore]
+async fn full_pipeline_against_live_feeds() {
+    let channels = takeout::parse_csv(CSV).expect("CSV should parse");
+    println!("parsed {} channels", channels.len());
+    assert!(channels.len() >= 10);
+
+    let mut db = Db::open_in_memory_pub().expect("db");
+    db.upsert_channels(&channels).unwrap();
+
+    let http = reqwest::Client::builder()
+        .user_agent("FlightTube/0.1 (+desktop)")
+        .timeout(std::time::Duration::from_secs(20))
+        .build()
+        .unwrap();
+
+    let mut total = 0;
+    for c in &channels {
+        match feed::fetch_channel(&http, &c.id).await {
+            Ok(v) => {
+                println!("  {:<30} {} videos", c.title, v.len());
+                total += v.len();
+                db.upsert_videos(&v).unwrap();
+            }
+            Err(e) => println!("  {:<30} FAILED: {e}", c.title),
+        }
+    }
+    assert!(total > 50, "expected a real feed, got {total} videos");
+
+    let all = db.list_feed(&FeedFilter::default()).unwrap();
+    println!("\nfeed rows: {}", all.len());
+
+    // The whole point: newest first, across all channels.
+    for w in all.windows(2) {
+        assert!(w[0].published >= w[1].published, "feed must be newest-first");
+    }
+    println!("top 5 newest across all subscriptions:");
+    for item in all.iter().take(5) {
+        println!(
+            "  [{}] {} — {}",
+            item.channel_title,
+            item.title.chars().take(60).collect::<String>(),
+            item.published
+        );
+    }
+
+    let no_shorts = db
+        .list_feed(&FeedFilter { hide_shorts: true, ..Default::default() })
+        .unwrap();
+    println!("\nwith shorts hidden: {} (was {})", no_shorts.len(), all.len());
+    assert!(no_shorts.len() <= all.len());
+    assert!(no_shorts.iter().all(|i| !i.is_short));
+
+    // Nothing is downloaded, so the offline view must be empty.
+    let offline = db
+        .list_feed(&FeedFilter { downloaded_only: true, ..Default::default() })
+        .unwrap();
+    assert_eq!(offline.len(), 0, "nothing downloaded yet");
+    println!("offline view with no downloads: {} rows (correct)", offline.len());
+}