fix(data-store-form): add change detection, fix button class, restore textarea height

- Add original_obj prop + has_changes bindable output to element_data_store_form
- Derive has_changes by comparing each draft field to original_obj; null = always dirty (new record)
- Wire bind:has_changes + original_obj={is_new ? null : editing_obj} in management page
- Fix Save button: preset-filled-primary → preset-filled-primary-500 (matches element_data_store)
- Disable Save when !has_changes; block modal outsideclose when changes are pending
- Restore textarea rows 10 → 15 to match element_data_store.svelte

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/elements/element_data_store_form.svelte

@@ -6,7 +6,12 @@
  * Usage contexts:
  *   - /core/data_stores/ management page (full fields, show_for_fields=true)
  *   - element_data_store.svelte inline editor (show_for_fields=false, show_account_field=false)
+ *
+ * Change detection: pass original_obj (the unmodified record) to enable has_changes.
+ * For new records, pass original_obj=null — has_changes will always be true.
+ * The parent can read changes via bind:has_changes.
  */
+import type { ae_DataStore } from '$lib/types/ae_types';
 import { ChevronDown, ChevronUp, Code, Eye } from '@lucide/svelte';
 import AE_Comp_Editor_CodeMirror from '$lib/elements/element_editor_codemirror.svelte';
 import AE_Comp_Editor_TipTap from '$lib/elements/element_editor_tiptap.svelte';
@@ -36,6 +41,11 @@ interface Props {
     show_account_field?: boolean;  // show account_id text input (false for embedded widget)
     show_for_fields?: boolean;     // show for_type + for_id (false for embedded widget)
     readonly_code?: boolean;       // lock the code field (non-manager users)
+
+    // Change detection — pass the unmodified record; null/undefined = new record (always dirty)
+    original_obj?: ae_DataStore | null;
+    // Bindable output: true when any draft field differs from original_obj (or always true for new records)
+    has_changes?: boolean;
 }
 
 let {
@@ -56,11 +66,38 @@ let {
     show_account_field = true,
     show_for_fields    = true,
     readonly_code      = false,
+    original_obj       = null,
+    has_changes        = $bindable(false),
 }: Props = $props();
 
 // Internal — not bindable; resets automatically when parent uses {#key} on record change
 let html_edit_mode = $state<'source' | 'visual'>('source');
 let show_advanced  = $state(false);
+
+// Compare each draft field to the original to detect unsaved changes.
+// new records (original_obj = null) are always considered dirty so Save is never blocked.
+let _has_changes = $derived.by(() => {
+    if (!original_obj) return true;
+    const orig_value = original_obj.type === 'json'
+        ? (typeof original_obj.json === 'string' ? original_obj.json : JSON.stringify(original_obj.json ?? '', null, 2))
+        : (original_obj.text || original_obj.html || '');
+    return (
+        draft_code     !== (original_obj.code    ?? '')    ||
+        draft_name     !== (original_obj.name    ?? '')    ||
+        draft_type     !== (original_obj.type    ?? 'text') ||
+        draft_value    !== orig_value                      ||
+        draft_account_id !== (original_obj.account_id ?? '') ||
+        draft_enable   !== (original_obj.enable  !== false) ||
+        draft_hide     !== !!original_obj.hide             ||
+        draft_priority !== !!original_obj.priority         ||
+        draft_sort     !== String(original_obj.sort  ?? '') ||
+        draft_group    !== (original_obj.group   ?? '')    ||
+        draft_notes    !== (original_obj.notes   ?? '')
+    );
+});
+
+// Push computed value out to the parent via the bindable prop
+$effect(() => { has_changes = _has_changes; });
 </script>
 
 <div class="space-y-4">
@@ -224,7 +261,7 @@ let show_advanced  = $state(false);
             <textarea
                 bind:value={draft_value}
                 class="textarea font-mono text-sm"
-                rows="10"
+                rows="15"
                 placeholder="Enter text content…"></textarea>
         {/if}
     </div>

src/routes/core/data_stores/+page.svelte

@@ -71,6 +71,7 @@ let draft_sort = $state('');
 let draft_group = $state('');
 let draft_notes = $state('');
 let submit_status = $state<'idle' | 'processing' | 'saved' | 'error'>('idle');
+let has_changes = $state(false); // bound from form component — true when any draft differs from editing_obj
 
 // ── Bulk rename state ─────────────────────────────────────────────────────────
 let show_bulk_rename = $state(false);
@@ -734,7 +735,7 @@ function content_preview(ds: ae_DataStore): string {
     title={is_new ? 'New Data Store' : `Edit: ${editing_obj?.code ?? ''}`}
     bind:open={show_edit}
     autoclose={false}
-    outsideclose={submit_status !== 'processing'}
+    outsideclose={!has_changes}
     size="xl"
     class="w-full max-w-5xl">
 
@@ -758,7 +759,9 @@ function content_preview(ds: ae_DataStore): string {
                 bind:draft_sort
                 bind:draft_group
                 bind:draft_notes
-                {is_new} />
+                {is_new}
+                original_obj={is_new ? null : editing_obj}
+                bind:has_changes />
         {/key}
 
         <!-- Footer actions -->
@@ -785,8 +788,8 @@ function content_preview(ds: ae_DataStore): string {
                 </button>
                 <button
                     type="submit"
-                    class="btn preset-filled-primary"
+                    class="btn preset-filled-primary-500"
-                    disabled={submit_status === 'processing'}
+                    disabled={!has_changes || submit_status === 'processing'}
                     title={is_new ? 'Create new data store' : 'Save changes'}>
                     {#if submit_status === 'processing'}
                         <LoaderCircle size={14} class="mr-2 animate-spin" />