feat(sidebar): add visible database filters

tests/visibleDatabases.test.ts

@@ -0,0 +1,32 @@
+import { strict as assert } from "node:assert";
+import test from "node:test";
+import {
+  filterVisibleDatabaseNames,
+  normalizeVisibleDatabaseSelection,
+  visibleDatabaseFilterIsEnabled,
+} from "../src/lib/visibleDatabases.ts";
+
+test("undefined visible database filter keeps every database", () => {
+  assert.deepEqual(filterVisibleDatabaseNames(["app", "analytics"], undefined), ["app", "analytics"]);
+  assert.equal(visibleDatabaseFilterIsEnabled(undefined), false);
+});
+
+test("configured visible database filter keeps selected databases in source order", () => {
+  assert.deepEqual(filterVisibleDatabaseNames(["app", "analytics", "billing"], ["billing", "app"]), [
+    "app",
+    "billing",
+  ]);
+  assert.equal(visibleDatabaseFilterIsEnabled(["billing", "app"]), true);
+});
+
+test("empty configured visible database filter hides every database", () => {
+  assert.deepEqual(filterVisibleDatabaseNames(["app", "analytics"], []), []);
+  assert.equal(visibleDatabaseFilterIsEnabled([]), true);
+});
+
+test("normalizes selected database names against fresh database names", () => {
+  assert.deepEqual(normalizeVisibleDatabaseSelection(["billing", "missing", "app", "app"], ["app", "billing"]), [
+    "billing",
+    "app",
+  ]);
+});