fix(automation): make deleting a trigger idempotent

Review pointed out that reconciling triggers breaks if one of them is deleted
by someone else first. The form deletes sequentially and the server rejected a
delete for a trigger that was already gone, so the whole save failed — and
failed again on every retry, because the trigger the form still wants removed
can never be removed. Two operators with the settings panel open, or a project
import that replaces the automation block, is enough to reach it.

Fixing that in the form would have meant recognising "already gone" from an
error message, since the refusal comes back as a 400 like any other. The
server is the better place: deleteAutomation fifty lines below already returns
early for an id it cannot find, for exactly this reason, so the two delete
functions now agree with each other and with what DELETE is supposed to mean.
Nothing depended on the throw — the controller was its only caller and no test
covered it.

Verified end to end: with the automation form open and its lifecycle unticked,
another client deletes that trigger, and the save now completes and closes
rather than failing with an error the user cannot clear.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AfDKsy6PE3Rbyt32Fg4YKf

apps/server/src/api-data/automation/__tests__/automation.dao.test.ts

@@ -116,6 +116,14 @@ describe('deleteTrigger()', () => {
     expect(removed.length).toEqual(1);
     expect(removed[0].title).not.toEqual('test-osc');
   });
+
+  it('ignores a trigger that is already gone', async () => {
+    // a client reconciling several triggers must not be stuck because another client
+    // removed one of them first: the end state it asked for is the one it gets
+    const before = getAutomationTriggers();
+    await expect(deleteTrigger('never-existed')).resolves.toBeUndefined();
+    expect(getAutomationTriggers()).toEqual(before);
+  });
 });
 
 describe('addAutomation()', () => {

apps/server/src/api-data/automation/automation.dao.ts

@@ -84,15 +84,17 @@ export async function editTrigger(id: string, newTrigger: TriggerDTO): Promise<T
  * Deletes an automation trigger given its ID
  */
 export async function deleteTrigger(id: string): Promise<void> {
-  let triggers = getAutomationTriggers();
+  const triggers = getAutomationTriggers();
   const index = triggers.findIndex((trigger) => trigger.id === id);
 
+  // ignore request if the trigger does not exist, as deleteAutomation does for the same reason:
+  // the caller asked for it to be gone and it is, and failing here makes a client that is
+  // reconciling several triggers unable to finish once another client removed one of them
   if (index === -1) {
-    throw new Error(`Automation with id ${id} not found`);
+    return;
   }
 
-  triggers = deleteAtIndex(index, triggers);
+  await saveChanges({ triggers: deleteAtIndex(index, triggers) });
-  await saveChanges({ triggers });
 }
 
 /**