fix(web): suppress global error toast on mutations that own their toast UX

Closes #1371. Retarget of #1385 onto dev per maintainer request.

surfsense_web/lib/query-client/client.ts configures a global
MutationCache.onError that shows an error toast for every failed
mutation unless meta.suppressGlobalErrorToast is set. The opt-out
hook existed in the consumer but had zero producers — every mutation
atom that already had its own onError: toast.error(...) was
double-toasting on failure.

Add meta: { suppressGlobalErrorToast: true } to the 30 mutations
across 9 atom files that own their own error toast:

- atoms/prompts/prompts-mutation.atoms.ts (4)
- atoms/invites/invites-mutation.atoms.ts (4)
- atoms/chat-comments/comments-mutation.atoms.ts (4)
- atoms/new-llm-config/new-llm-config-mutation.atoms.ts (4)
- atoms/members/members-mutation.atoms.ts (3)
- atoms/roles/roles-mutation.atoms.ts (3)
- atoms/image-gen-config/image-gen-config-mutation.atoms.ts (3)
- atoms/vision-llm-config/vision-llm-config-mutation.atoms.ts (3)
- atoms/public-chat-snapshots/public-chat-snapshots-mutation.atoms.ts (2)

Atoms intentionally left alone (no local onError, rely on global):
auth, user, search-spaces, logs, documents, connectors.

Local validation (against dev): pnpm biome check on the 9 touched
files is clean; tsc --noEmit shows no new errors in the touched files
(pre-existing errors elsewhere unrelated).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

surfsense_web/atoms/roles/roles-mutation.atoms.ts

@@ -14,6 +14,7 @@ import { queryClient } from "@/lib/query-client/client";
 
 export const createRoleMutationAtom = atomWithMutation(() => {
 	return {
+		meta: { suppressGlobalErrorToast: true },
 		mutationFn: async (request: CreateRoleRequest) => {
 			return rolesApiService.createRole(request);
 		},
@@ -31,6 +32,7 @@ export const createRoleMutationAtom = atomWithMutation(() => {
 
 export const updateRoleMutationAtom = atomWithMutation(() => {
 	return {
+		meta: { suppressGlobalErrorToast: true },
 		mutationFn: async (request: UpdateRoleRequest) => {
 			return rolesApiService.updateRole(request);
 		},
@@ -54,6 +56,7 @@ export const updateRoleMutationAtom = atomWithMutation(() => {
 
 export const deleteRoleMutationAtom = atomWithMutation(() => {
 	return {
+		meta: { suppressGlobalErrorToast: true },
 		mutationFn: async (request: DeleteRoleRequest) => {
 			return rolesApiService.deleteRole(request);
 		},