Add CPU/GPU names on perf charts, reusable color picker, and header toolbar redesign

- Show CPU and GPU model names as overlays on performance chart cards
- Add cpu_name field to performance API with cross-platform detection
- Extract reusable color-picker popover module (9 presets + custom picker)
- Per-chart color customization for CPU/RAM/GPU performance charts
- Redesign header: compact toolbar container with icon-only buttons
- Compact language dropdown (EN/RU/ZH), icon-only login/logout
- Use accent color for FPS charts, range slider accent, dashboard icons

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

server/src/wled_controller/api/routes/system.py

@@ -2,6 +2,7 @@
 
 import io
 import json
+import platform
 import subprocess
 import sys
 import threading
@@ -55,6 +56,40 @@ except Exception:
     _nvml = None
     logger.info("NVIDIA GPU monitoring unavailable (pynvml not installed or no NVIDIA GPU)")
 
+
+def _get_cpu_name() -> str | None:
+    """Get a human-friendly CPU model name (cached at module level)."""
+    try:
+        if platform.system() == "Windows":
+            import winreg
+
+            key = winreg.OpenKey(
+                winreg.HKEY_LOCAL_MACHINE,
+                r"HARDWARE\DESCRIPTION\System\CentralProcessor\0",
+            )
+            name, _ = winreg.QueryValueEx(key, "ProcessorNameString")
+            winreg.CloseKey(key)
+            return name.strip()
+        elif platform.system() == "Linux":
+            with open("/proc/cpuinfo") as f:
+                for line in f:
+                    if "model name" in line:
+                        return line.split(":")[1].strip()
+        elif platform.system() == "Darwin":
+            return (
+                subprocess.check_output(
+                    ["sysctl", "-n", "machdep.cpu.brand_string"]
+                )
+                .decode()
+                .strip()
+            )
+    except Exception:
+        pass
+    return platform.processor() or None
+
+
+_cpu_name: str | None = _get_cpu_name()
+
 router = APIRouter()
 
 
@@ -196,6 +231,7 @@ def get_system_performance(_: AuthRequired):
             pass
 
     return PerformanceResponse(
+        cpu_name=_cpu_name,
         cpu_percent=psutil.cpu_percent(interval=None),
         ram_used_mb=round(mem.used / 1024 / 1024, 1),
         ram_total_mb=round(mem.total / 1024 / 1024, 1),