add domain concepts: FillStrategy variants, Chapter, InterstitialRule, MidRollRule, gap_filler

- FillStrategy: +Alternating (round-robin series), +Weighted (fresh-first), +Marathon (always ep1, loops)
- Chapter value object on MediaItem (JSON column in library_items)
- InterstitialRule + MidRollRule on ProgrammingBlock (data model only)
- gap_filler: Option<MediaFilter> on Channel (persisted as JSON column)
- migration: 20260712000002_add_chapters_and_gap_filler.sql

crates/domain/src/models/channel.rs

@@ -3,8 +3,8 @@ use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 
 use crate::value_objects::{
-    AccessMode, BlockId, ChannelId, FillStrategy, LogoPosition, MediaFilter, MediaItemId,
-    RotationPolicy, UserId, Weekday,
+    AccessMode, BlockId, ChannelId, FillStrategy, InterstitialRule, LogoPosition, MediaFilter,
+    MediaItemId, MidRollRule, RotationPolicy, UserId, Weekday,
 };
 
 const SECONDS_IN_DAY: u32 = 86_400;
@@ -29,6 +29,8 @@ pub struct Channel {
     webhook_poll_interval_secs: u32,
     webhook_body_template: Option<String>,
     webhook_headers: Option<String>,
+    #[serde(default)]
+    gap_filler: Option<MediaFilter>,
     created_at: DateTime<Utc>,
     updated_at: DateTime<Utc>,
 }
@@ -50,6 +52,7 @@ pub struct ChannelRow {
     pub webhook_poll_interval_secs: u32,
     pub webhook_body_template: Option<String>,
     pub webhook_headers: Option<String>,
+    pub gap_filler: Option<MediaFilter>,
     pub created_at: DateTime<Utc>,
     pub updated_at: DateTime<Utc>,
 }
@@ -78,6 +81,7 @@ impl Channel {
             webhook_poll_interval_secs: DEFAULT_WEBHOOK_POLL_INTERVAL_SECS,
             webhook_body_template: None,
             webhook_headers: None,
+            gap_filler: None,
             created_at: now,
             updated_at: now,
         }
@@ -101,6 +105,7 @@ impl Channel {
             webhook_poll_interval_secs: row.webhook_poll_interval_secs,
             webhook_body_template: row.webhook_body_template,
             webhook_headers: row.webhook_headers,
+            gap_filler: row.gap_filler,
             created_at: row.created_at,
             updated_at: row.updated_at,
         }
@@ -207,6 +212,15 @@ impl Channel {
         self.auto_schedule = enabled;
         self.updated_at = Utc::now();
     }
+
+    pub fn gap_filler(&self) -> Option<&MediaFilter> {
+        self.gap_filler.as_ref()
+    }
+
+    pub fn set_gap_filler(&mut self, gap_filler: Option<MediaFilter>) {
+        self.gap_filler = gap_filler;
+        self.updated_at = Utc::now();
+    }
 }
 
 // deny_unknown_fields required so #[serde(untagged)] compat enum correctly rejects V1 payloads
@@ -324,6 +338,12 @@ pub struct ProgrammingBlock {
 
     #[serde(default)]
     ignore_rotation_policy: bool,
+
+    #[serde(default)]
+    interstitial_rule: Option<InterstitialRule>,
+
+    #[serde(default)]
+    mid_roll_rule: Option<MidRollRule>,
 }
 
 impl ProgrammingBlock {
@@ -345,6 +365,8 @@ impl ProgrammingBlock {
             },
             loop_on_finish: true,
             ignore_rotation_policy: false,
+            interstitial_rule: None,
+            mid_roll_rule: None,
         }
     }
 
@@ -364,6 +386,8 @@ impl ProgrammingBlock {
             },
             loop_on_finish: true,
             ignore_rotation_policy: false,
+            interstitial_rule: None,
+            mid_roll_rule: None,
         }
     }
 
@@ -394,6 +418,14 @@ impl ProgrammingBlock {
     pub fn ignore_rotation_policy(&self) -> bool {
         self.ignore_rotation_policy
     }
+
+    pub fn interstitial_rule(&self) -> Option<&InterstitialRule> {
+        self.interstitial_rule.as_ref()
+    }
+
+    pub fn mid_roll_rule(&self) -> Option<&MidRollRule> {
+        self.mid_roll_rule.as_ref()
+    }
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]