feat(automations): implement model eligibility checks for automation creation

- Added model eligibility checks to ensure automations can only use billable models (premium or BYOK).
- Introduced new API endpoint to report model eligibility status for search spaces.
- Updated frontend components to display eligibility alerts and disable creation options when models are not billable.
- Enhanced automation creation forms to reflect model eligibility, preventing users from submitting invalid configurations.
- Implemented server-side logic to capture and preserve model preferences across automation edits, ensuring consistent behavior during execution.

surfsense_web/atoms/new-llm-config/new-llm-config-mutation.atoms.ts

@@ -118,6 +118,12 @@ export const updateLLMPreferencesMutationAtom = atomWithMutation((get) => {
 				cacheKeys.newLLMConfigs.preferences(Number(searchSpaceId)),
 				(old: Record<string, unknown> | undefined) => ({ ...old, ...request.data })
 			);
+			// Automation eligibility is derived from these model preferences
+			// (agent/image/vision). Invalidate it so the automations gate alert
+			// reflects the new selection without a manual refresh.
+			queryClient.invalidateQueries({
+				queryKey: cacheKeys.automations.modelEligibility(Number(searchSpaceId)),
+			});
 		},
 		onError: (error: Error) => {
 			toast.error(error.message || "Failed to update LLM preferences");