signature: add systems map, command palette and motion primitives

Ship the Signature UX as standalone, SSR-safe pieces: bilingual copy, a dual SVG/list systems map, a Map-backed command palette in the shell, opt-in reveal and metric primitives, and a leak-free decorative canvas.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/core/content/signature-copy.spec.ts

@@ -0,0 +1,60 @@
+import { APP_LOCALES } from '../i18n/locale';
+import { COMMAND_IDS } from '../../shared/command-palette/commands';
+import { SIGNATURE_COPY } from './signature-copy';
+
+function leafPaths(value: unknown, prefix = ''): string[] {
+  if (typeof value === 'string') {
+    return [prefix];
+  }
+
+  if (value !== null && typeof value === 'object') {
+    return Object.keys(value).flatMap((key) => {
+      const next = prefix.length > 0 ? `${prefix}.${key}` : key;
+      return leafPaths((value as Record<string, unknown>)[key], next);
+    });
+  }
+
+  return [prefix];
+}
+
+function collectStrings(value: unknown): string[] {
+  if (typeof value === 'string') {
+    return [value];
+  }
+
+  if (value !== null && typeof value === 'object') {
+    return Object.values(value).flatMap((entry) => collectStrings(entry));
+  }
+
+  return [];
+}
+
+describe('SIGNATURE_COPY', () => {
+  it('exposes the same key structure in both locales', () => {
+    const [first, ...rest] = APP_LOCALES.map((locale) => leafPaths(SIGNATURE_COPY[locale]));
+
+    for (const keys of rest) {
+      expect(keys).toEqual(first);
+    }
+  });
+
+  it('keeps every string non-empty', () => {
+    for (const locale of APP_LOCALES) {
+      for (const value of collectStrings(SIGNATURE_COPY[locale])) {
+        expect(value.trim().length).toBeGreaterThan(0);
+      }
+    }
+  });
+
+  it('describes every CommandId in both locales', () => {
+    for (const locale of APP_LOCALES) {
+      const descriptions = SIGNATURE_COPY[locale].palette.commandDescriptions;
+
+      expect(Object.keys(descriptions).sort()).toEqual([...COMMAND_IDS].sort());
+
+      for (const id of COMMAND_IDS) {
+        expect(descriptions[id].trim().length).toBeGreaterThan(0);
+      }
+    }
+  });
+});