feat(home): animated typewriter placeholder for the prompt composer

Cycle through localized example prompts with a typing/deleting animation
in the home composer placeholder, start the field empty instead of with
a default prompt, and style the home editor with larger prompt text.

Also rebrand the device-management copy from Lovart to Moteva.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/ui/styles.css

@@ -137,6 +137,13 @@ button:disabled {
   cursor: text;
 }
 
+.prompt-rich-editor.home-prompt-editor {
+  color: #1f2937;
+  font-size: 24px;
+  line-height: 1.45;
+  font-weight: 600;
+}
+
 .prompt-rich-editor[data-empty="true"]::before {
   position: absolute;
   top: 0;
@@ -146,6 +153,10 @@ button:disabled {
   pointer-events: none;
 }
 
+.prompt-rich-editor.home-prompt-editor[data-empty="true"]::before {
+  color: #b5b7bc;
+}
+
 .prompt-card.has-references .prompt-rich-editor {
   min-height: 118px;
 }