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

migrations/V13__owner_scope_notify_targets.sql

@@ -0,0 +1,11 @@
+-- Remove the legacy 'default' sentinel from routine notifications.
+-- A NULL notify_user now means "resolve the configured owner's last-seen
+-- channel target at send time."
+
+ALTER TABLE routines
+    ALTER COLUMN notify_user DROP NOT NULL,
+    ALTER COLUMN notify_user DROP DEFAULT;
+
+UPDATE routines
+SET notify_user = NULL
+WHERE notify_user = 'default';

migrations/V6__routines.sql

@@ -26,7 +26,7 @@ CREATE TABLE routines (
 
     -- Notification preferences
     notify_channel TEXT,                 -- NULL = use default
-    notify_user TEXT NOT NULL DEFAULT 'default',
+    notify_user TEXT,
     notify_on_success BOOLEAN NOT NULL DEFAULT false,
     notify_on_failure BOOLEAN NOT NULL DEFAULT true,
     notify_on_attention BOOLEAN NOT NULL DEFAULT true,