Merge templates into Streams tab, rename app to WLED Grab

- Merge Capture Templates and Processing Templates main tabs into Picture
  Streams sub-tabs (Screen Capture shows streams + engine templates,
  Processed shows streams + filter templates)
- Rename "Capture Templates" to "Engine Templates" and "Processing
  Templates" to "Filter Templates" across all locale strings
- Rename "Picture Streams" tab to "Streams" throughout UI and locales
- Rename "WLED Screen Controller" to "WLED Grab" across all files
- Add subtab section headers and styling for merged template views
- Remove add card labels, keeping only plus icon for cleaner UI

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

server/src/wled_controller/main.py

@@ -98,7 +98,7 @@ async def lifespan(app: FastAPI):
     Handles startup and shutdown events.
     """
     # Startup
-    logger.info(f"Starting WLED Screen Controller v{__version__}")
+    logger.info(f"Starting WLED Grab v{__version__}")
     logger.info(f"Python version: {sys.version}")
     logger.info(f"Server listening on {config.server.host}:{config.server.port}")
 
@@ -152,7 +152,7 @@ async def lifespan(app: FastAPI):
     yield
 
     # Shutdown
-    logger.info("Shutting down WLED Screen Controller")
+    logger.info("Shutting down WLED Grab")
 
     # Stop all processing
     try:
@@ -163,7 +163,7 @@ async def lifespan(app: FastAPI):
 
 # Create FastAPI application
 app = FastAPI(
-    title="WLED Screen Controller",
+    title="WLED Grab",
     description="Control WLED devices based on screen content for ambient lighting",
     version=__version__,
     lifespan=lifespan,
@@ -217,7 +217,7 @@ async def root():
 
     # Fallback to JSON if static files not found
     return {
-        "name": "WLED Screen Controller",
+        "name": "WLED Grab",
         "version": __version__,
         "docs": "/docs",
         "health": "/health",