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/config.py

@@ -1,4 +1,4 @@
-"""Configuration management for WLED Grab."""
+"""Configuration management for LED Grab."""
 
 import os
 from pathlib import Path