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/application/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2024"
 domain = { workspace = true }
 async-trait = { workspace = true }
 chrono = { workspace = true }
+serde_json = { workspace = true }
 uuid = { workspace = true }
 
 [dev-dependencies]