feat: add webhook body template and headers support for channels

k-tv-backend/api/src/dto.rs

@@ -74,6 +74,8 @@ pub struct CreateChannelRequest {
     pub access_password: Option<String>,
     pub webhook_url: Option<String>,
     pub webhook_poll_interval_secs: Option<u32>,
+    pub webhook_body_template: Option<String>,
+    pub webhook_headers: Option<String>,
 }
 
 /// All fields are optional — only provided fields are updated.
@@ -96,6 +98,10 @@ pub struct UpdateChannelRequest {
     /// `Some(None)` = clear, `Some(Some(url))` = set, `None` = unchanged.
     pub webhook_url: Option<Option<String>>,
     pub webhook_poll_interval_secs: Option<u32>,
+    /// `Some(None)` = clear, `Some(Some(tmpl))` = set, `None` = unchanged.
+    pub webhook_body_template: Option<Option<String>>,
+    /// `Some(None)` = clear, `Some(Some(json))` = set, `None` = unchanged.
+    pub webhook_headers: Option<Option<String>>,
 }
 
 #[derive(Debug, Serialize)]
@@ -114,6 +120,8 @@ pub struct ChannelResponse {
     pub logo_opacity: f32,
     pub webhook_url: Option<String>,
     pub webhook_poll_interval_secs: u32,
+    pub webhook_body_template: Option<String>,
+    pub webhook_headers: Option<String>,
     pub created_at: DateTime<Utc>,
     pub updated_at: DateTime<Utc>,
 }
@@ -135,6 +143,8 @@ impl From<domain::Channel> for ChannelResponse {
             logo_opacity: c.logo_opacity,
             webhook_url: c.webhook_url,
             webhook_poll_interval_secs: c.webhook_poll_interval_secs,
+            webhook_body_template: c.webhook_body_template,
+            webhook_headers: c.webhook_headers,
             created_at: c.created_at,
             updated_at: c.updated_at,
         }