feat(FN-800): auto-generate model preset IDs and remove manual ID editing

- Add slugify and generatePresetId utilities with collision handling for unique preset IDs
- Remove manual ID input field from preset editor UI in SettingsModal
- Auto-generate preset IDs server-side from name on creation
- Simplify Header tests by removing ID-related test cases
- Deduplicate tablet header controls tests by importing from shared Header tests
- Remove unused CSS rules for removed ID input field
- Update reviewer to pass through preset ID generation logic

packages/dashboard/app/utils/modelPresets.ts

@@ -45,3 +45,26 @@ export function generatePresetId(name: string): string {
 
   return slug || "preset";
 }
+
+/**
+ * Generate a unique preset ID derived from the preset name, avoiding collisions
+ * with existing preset IDs. If the base slug is already taken, appends `-1`,
+ * `-2`, etc. until a unique ID is found.
+ */
+export function generateUniquePresetId(name: string, existingPresets: ModelPreset[]): string {
+  const baseId = generatePresetId(name);
+  const takenIds = new Set(existingPresets.map((p) => p.id));
+
+  if (!takenIds.has(baseId)) return baseId;
+
+  // Leave room for the numeric suffix (-N)
+  const maxBase = 30;
+  let candidate = baseId;
+  let idx = 1;
+  while (takenIds.has(candidate) && idx < 100) {
+    const suffix = `-${idx}`;
+    candidate = `${baseId.slice(0, maxBase - suffix.length)}${suffix}`;
+    idx++;
+  }
+  return candidate;
+}