Rename WLED Grab to LED Grab, merge Devices into Targets tab with WLED sub-tab, and UI polish

- Rename "WLED Grab" to "LED Grab" across all files (title, logs, locales)
- Merge Devices and Targets into a single Targets tab with WLED sub-tab
  containing Devices and Targets sections (like Sources tab pattern)
- Make target card source name label full-width
- Render engine template config as two-column key-value grid
- Update CLAUDE.md: no server restart needed for frontend-only changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/locales/en.json

@@ -1,5 +1,5 @@
 {
-  "app.title": "WLED Grab",
+  "app.title": "LED Grab",
   "app.version": "Version:",
   "theme.toggle": "Toggle theme",
   "locale.change": "Change language",
@@ -7,7 +7,7 @@
   "auth.logout": "Logout",
   "auth.authenticated": "● Authenticated",
   "auth.title": "Login to WLED Controller",
-  "auth.message": "Please enter your API key to authenticate and access the WLED Grab.",
+  "auth.message": "Please enter your API key to authenticate and access the LED Grab.",
   "auth.label": "API Key:",
   "auth.placeholder": "Enter your API key...",
   "auth.hint": "Your API key will be stored securely in your browser's local storage.",
@@ -301,6 +301,9 @@
   "streams.validate_image.invalid": "Image not accessible",
   "targets.title": "⚡ Targets",
   "targets.description": "Targets bridge picture sources to output devices. Each target references a device and a source, with its own processing settings.",
+  "targets.subtab.wled": "WLED",
+  "targets.section.devices": "💡 Devices",
+  "targets.section.targets": "⚡ Targets",
   "targets.add": "Add Target",
   "targets.edit": "Edit Target",
   "targets.loading": "Loading targets...",