feat(cli): comprehensive docs, version bump, and purple branding (#4680)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cli/node/tests/branding.test.ts

@@ -39,7 +39,7 @@ afterEach(() => {
 
 describe("branding constants", () => {
   it("has correct brand color", () => {
-    expect(BRAND_COLOR).toBe("#F1C96C");
+    expect(BRAND_COLOR).toBe("#8b5cf6");
   });
 
   it("has correct tagline", () => {