Refactor owner scope across channels and fix default routing fallback (#1151)

* refactor: add explicit owner scope across channels

* fix: tighten routine owner target routing

* fix: address owner scope review feedback

* Fix owner-scope onboarding and event trigger isolation

* Tighten routing fallback and wizard owner validation

* fix: address owner-scope follow-up review

* fix: tighten owner-scope follow-up details

* fix: import Channel trait in telegram test

* fix: normalize http webhook sender ids

* fix: address remaining owner-scope review issues

* fix: reconcile config rebase fallout

* fix: reconcile extension manager rebase drift

* fix: address current copilot review regressions

* fix: restore clippy matrix after rebase

src/tools/builtin/routine.rs

@@ -106,7 +106,7 @@ pub(crate) fn routine_create_parameters_schema() -> serde_json::Value {
             },
             "notify_user": {
                 "type": "string",
-                "description": "User or destination to notify, for example a username or chat ID."
+                "description": "Optional explicit user or destination to notify, for example a username or chat ID. Omit it to use the configured owner's last-seen target for that channel."
             },
             "timezone": {
                 "type": "string",
@@ -387,8 +387,7 @@ impl Tool for RoutineCreateTool {
                 user: params
                     .get("notify_user")
                     .and_then(|v| v.as_str())
-                    .unwrap_or("default")
-                    .to_string(),
+                    .map(String::from),
                 ..NotifyConfig::default()
             },
             last_run_at: None,