domain crate code quality cleanup

strip all comments, extract tests to tests/ dirs,
remove #[allow(clippy::...)], extract magic numbers to
constants, refactor schedule engine private methods to
use param structs, add Default impls, clippy.toml for
persistence constructors

crates/domain/src/models/tests/channel.rs

@@ -0,0 +1,111 @@
+use super::*;
+
+fn t(h: u32, m: u32) -> NaiveTime {
+    NaiveTime::from_hms_opt(h, m, 0).unwrap()
+}
+
+fn make_block(start: NaiveTime, duration_mins: u32) -> ProgrammingBlock {
+    ProgrammingBlock::new_algorithmic(
+        "test",
+        start,
+        duration_mins,
+        Default::default(),
+        FillStrategy::Random,
+    )
+}
+
+fn cfg_with_monday_block(start: NaiveTime, dur: u32) -> ScheduleConfig {
+    let mut cfg = ScheduleConfig::default();
+    cfg.insert_day(Weekday::Monday, vec![make_block(start, dur)]);
+    cfg
+}
+
+#[test]
+fn find_block_at_finds_active_block() {
+    let cfg = cfg_with_monday_block(t(8, 0), 60);
+    assert!(cfg.find_block_at(Weekday::Monday, t(8, 30)).is_some());
+    assert!(cfg.find_block_at(Weekday::Monday, t(9, 0)).is_none());
+}
+
+#[test]
+fn find_block_at_wrong_day_returns_none() {
+    let cfg = cfg_with_monday_block(t(8, 0), 60);
+    assert!(cfg.find_block_at(Weekday::Tuesday, t(8, 30)).is_none());
+}
+
+#[test]
+fn v1_compat_copies_blocks_to_all_days() {
+    let json = r#"{"blocks": []}"#;
+    let compat: ScheduleConfigCompat = serde_json::from_str(json).unwrap();
+    let cfg: ScheduleConfig = compat.into();
+    assert_eq!(cfg.day_blocks().len(), 7);
+}
+
+#[test]
+fn v2_payload_with_unknown_blocks_key_fails() {
+    let json = r#"{"blocks": [], "day_blocks": {}}"#;
+    let result: Result<ScheduleConfigCompat, _> = serde_json::from_str(json);
+    match result {
+        Ok(ScheduleConfigCompat::V2(cfg)) => {
+            let _ = cfg;
+        }
+        Ok(ScheduleConfigCompat::V1(_)) => {}
+        Err(_) => {}
+    }
+}
+
+#[test]
+fn earliest_block_start_across_days() {
+    let mut cfg = ScheduleConfig::default();
+    cfg.insert_day(Weekday::Monday, vec![make_block(t(10, 0), 60)]);
+    cfg.insert_day(Weekday::Friday, vec![make_block(t(7, 0), 60)]);
+    assert_eq!(cfg.earliest_block_start(), Some(t(7, 0)));
+}
+
+#[test]
+fn empty_config_earliest_block_start_is_none() {
+    let cfg = ScheduleConfig::default();
+    assert!(cfg.earliest_block_start().is_none());
+}
+
+#[test]
+fn channel_new_defaults() {
+    let owner = UserId::generate();
+    let ch = Channel::new(owner, "Test Channel", "America/New_York");
+    assert_eq!(ch.name(), "Test Channel");
+    assert_eq!(ch.timezone(), "America/New_York");
+    assert_eq!(ch.owner_id(), owner);
+    assert!(!ch.auto_schedule());
+    assert!(ch.description().is_none());
+    assert_eq!(ch.logo_opacity(), DEFAULT_LOGO_OPACITY);
+    assert_eq!(ch.webhook_poll_interval_secs(), DEFAULT_WEBHOOK_POLL_INTERVAL_SECS);
+}
+
+#[test]
+fn programming_block_getters() {
+    let block = ProgrammingBlock::new_algorithmic(
+        "Morning",
+        t(8, 0),
+        120,
+        Default::default(),
+        FillStrategy::BestFit,
+    );
+    assert_eq!(block.name(), "Morning");
+    assert_eq!(block.start_time(), t(8, 0));
+    assert_eq!(block.duration_mins(), 120);
+    assert!(block.loop_on_finish());
+    assert!(!block.ignore_recycle_policy());
+}
+
+#[test]
+fn manual_block_creation() {
+    let items = vec![MediaItemId::new("item1"), MediaItemId::new("item2")];
+    let block = ProgrammingBlock::new_manual("Manual Block", t(20, 0), 60, items);
+    match block.content() {
+        BlockContent::Manual { items, provider_id } => {
+            assert_eq!(items.len(), 2);
+            assert!(provider_id.is_empty());
+        }
+        _ => panic!("Expected Manual content"),
+    }
+}