feat(ux): epic UX design improvements across agents, chat, notes, and i18n

Comprehensive UI/UX updates including agent card redesign, chat container
improvements, note editor enhancements, memory echo notifications, and
updated translations for all 15 locales.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.playwright-mcp/page-2026-04-19T18-53-33-247Z.yml

@@ -0,0 +1,21 @@
+- generic [active] [ref=e1]:
+  - main [ref=e4]:
+    - generic [ref=e7]:
+      - heading "Sign in to your account" [level=1] [ref=e8]
+      - generic [ref=e9]:
+        - generic [ref=e10]:
+          - generic [ref=e11]: Email
+          - textbox "Email" [ref=e13]:
+            - /placeholder: Enter your email address
+        - generic [ref=e14]:
+          - generic [ref=e15]: Password
+          - textbox "Password" [ref=e17]:
+            - /placeholder: Enter your password
+      - link "Forgot password?" [ref=e19] [cursor=pointer]:
+        - /url: /forgot-password
+      - button "Sign In" [ref=e20]
+      - generic [ref=e22]:
+        - text: Don't have an account?
+        - link "Sign Up" [ref=e23] [cursor=pointer]:
+          - /url: /register
+  - region "Notifications alt+T"