refactor: move useSignatureTextPolicy to signature-text feature folder

- Move useSignatureTextPolicy.ts from src/composables/ to feature folder
- Co-localize composable with signature-text policy editor components
- Eliminates scope leak - composable specific to signature-text feature
- Update import in SignatureStamp.vue
- Improves code organization and feature cohesion

Author: vitormattos

src/composables/useSignatureTextPolicy.ts …signature-text/useSignatureTextPolicy.tssrc/composables/useSignatureTextPolicy.ts renamed to src/views/Settings/PolicyWorkbench/settings/signature-text/useSignatureTextPolicy.ts src/composables/useSignatureTextPolicy.ts renamed to src/views/Settings/PolicyWorkbench/settings/signature-text/useSignatureTextPolicy.ts

@@ -5,7 +5,7 @@
 
 import { computed } from 'vue'
 import { loadState } from '@nextcloud/initial-state'
-import { usePoliciesStore } from '../store/policies'
+import { usePoliciesStore } from '../../../../../store/policies'
 
 // Defaults matching backend SignatureTextPolicyValue::DEFAULTS
 const SIGNATURE_TEXT_DEFAULTS = {

src/views/Settings/SignatureStamp.vue

@@ -356,7 +356,7 @@ import NcTextField from '@nextcloud/vue/components/NcTextField'
 import { useIsDarkTheme } from '@nextcloud/vue/composables/useIsDarkTheme'
 
 import CodeEditor from '../../components/CodeEditor.vue'
-import { useSignatureTextPolicy } from '../../composables/useSignatureTextPolicy'
+import { useSignatureTextPolicy } from './PolicyWorkbench/settings/signature-text/useSignatureTextPolicy'
 
 defineOptions({
 	name: 'SignatureStamp',