Fix shell details: distro name, storage path only in footer

- OS name comes from /etc/os-release (e.g. 'CachyOS Linux'), mirroring
  the original app's os_utils; macOS/Windows get proper names too
- Status pill shows the name as-is instead of uppercasing it
- Removed the watched-folder path next to the logo; it now appears only
  in the footer strip (spec updated to match)

backend/apps/core/system_info.py

@@ -0,0 +1,33 @@
+import platform
+from functools import lru_cache
+
+
+@lru_cache(maxsize=1)
+def _os_release_values():
+    values = {}
+    try:
+        with open("/etc/os-release", encoding="utf-8") as handle:
+            for line in handle:
+                line = line.strip()
+                if not line or "=" not in line:
+                    continue
+                key, value = line.split("=", 1)
+                values[key] = value.strip().strip('"')
+    except OSError:
+        pass
+    return values
+
+
+@lru_cache(maxsize=1)
+def get_os_info():
+    """OS display name and icon key, mirroring the original app's os_utils."""
+    system = platform.system()
+    release = platform.release()
+    if system == "Linux":
+        name = _os_release_values().get("NAME") or "Linux"
+        return {"name": name, "release": release, "icon": "linux"}
+    if system == "Darwin":
+        return {"name": "macOS", "release": release, "icon": "apple"}
+    if system == "Windows":
+        return {"name": "Windows", "release": release, "icon": "windows"}
+    return {"name": system, "release": release, "icon": "unknown"}