fix(presentation): extract 12 handler violations to use cases

- TokenService port + JwtTokenService adapter; login/refresh return LoginResult
- delete get_token (dup of login); create_tokens helper removed
- type UpdateChannelRequest schedule_config/recycle_policy (no serde_json::Value)
- update_settings returns updated Vec; handler calls one use case
- config use case in application::config; handler maps DTO only
- SyncStatusEntry moved to api-types w/ From<LibrarySyncLogEntry>
- trigger_sync: Conflict error, drop sync_trigger.send from handler
- UpsertProviderCommand.config accepts Value; serialization in use case
- get_current_broadcast returns BroadcastWithChannel; one call
- get_stream_url resolves broadcast internally; handler single call

crates/presentation/src/handlers/admin.rs

@@ -3,7 +3,7 @@ use axum::extract::{Query, State};
 use std::collections::HashMap;
 
 use api_types::{ActivityEventResponse, ActivityLogParams, SettingsResponse};
-use application::admin::{GetActivityLogQuery, GetSettingsQuery, UpdateSettingsCommand};
+use application::admin::{GetActivityLogQuery, UpdateSettingsCommand};
 
 use crate::errors::AppError;
 use crate::extractors::AdminUser;
@@ -16,7 +16,7 @@ pub async fn get_settings(
     AdminUser(_user): AdminUser,
 ) -> Result<Json<SettingsResponse>, AppError> {
     let pairs =
-        application::admin::get_settings::execute(&state.admin_deps, GetSettingsQuery).await?;
+        application::admin::get_settings::execute(&state.admin_deps, application::admin::GetSettingsQuery).await?;
     let settings: HashMap<String, String> = pairs.into_iter().collect();
     Ok(Json(SettingsResponse { settings }))
 }
@@ -30,10 +30,7 @@ pub async fn update_settings(
     let cmd = UpdateSettingsCommand {
         settings: settings_vec,
     };
-    application::admin::update_settings::execute(&state.admin_deps, cmd).await?;
-
-    let pairs =
-        application::admin::get_settings::execute(&state.admin_deps, GetSettingsQuery).await?;
+    let pairs = application::admin::update_settings::execute(&state.admin_deps, cmd).await?;
     let settings: HashMap<String, String> = pairs.into_iter().collect();
     Ok(Json(SettingsResponse { settings }))
 }