fix(builds): repair inventar settings import and add skilltree storage service

- inventar-web: fix mangled icon import in settings page
- skilltree-web: create missing lib/services/storage.ts for export/import
- startup.sh: add umami/synapse DB creation + synapse user setup with C locale

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

apps/skilltree/apps/web/src/lib/services/storage.ts

@@ -0,0 +1,32 @@
+import { skillCollection, activityCollection, achievementCollection } from '$lib/data/local-store';
+
+export async function exportData() {
+	const [skills, activities, achievements] = await Promise.all([
+		skillCollection.getAll(),
+		activityCollection.getAll(),
+		achievementCollection.getAll(),
+	]);
+	return { skills, activities, achievements, exportedAt: new Date().toISOString() };
+}
+
+export async function importData(data: {
+	skills?: unknown[];
+	activities?: unknown[];
+	achievements?: unknown[];
+}) {
+	if (Array.isArray(data.skills)) {
+		for (const skill of data.skills) {
+			await skillCollection.insert(skill as never).catch(() => null);
+		}
+	}
+	if (Array.isArray(data.activities)) {
+		for (const activity of data.activities) {
+			await activityCollection.insert(activity as never).catch(() => null);
+		}
+	}
+	if (Array.isArray(data.achievements)) {
+		for (const achievement of data.achievements) {
+			await achievementCollection.insert(achievement as never).catch(() => null);
+		}
+	}
+}