Add Loki and Sentinel utility classes for web API endpoints

- Implemented LokiUtils class with GET and POST endpoints for managing scripts, jobs, and payloads.
- Added SentinelUtils class with GET and POST endpoints for managing events, rules, devices, and notifications.
- Both classes include error handling and JSON response formatting.

loki/layouts/__init__.py

@@ -0,0 +1,45 @@
+"""
+Keyboard layout loader for Loki HID subsystem.
+Caches loaded layouts in memory.
+"""
+import json
+import os
+import logging
+
+from logger import Logger
+
+logger = Logger(name="loki.layouts", level=logging.DEBUG)
+
+_LAYOUT_DIR = os.path.dirname(os.path.abspath(__file__))
+_cache = {}
+
+
+def load(name: str = "us") -> dict:
+    """Load a keyboard layout by name. Returns char → (modifier, keycode) map."""
+    name = name.lower()
+    if name in _cache:
+        return _cache[name]
+
+    path = os.path.join(_LAYOUT_DIR, f"{name}.json")
+    if not os.path.isfile(path):
+        logger.warning("Layout '%s' not found, falling back to 'us'", name)
+        path = os.path.join(_LAYOUT_DIR, "us.json")
+        name = "us"
+        if name in _cache:
+            return _cache[name]
+
+    with open(path, "r") as f:
+        data = json.load(f)
+
+    _cache[name] = data
+    logger.debug("Loaded keyboard layout '%s' (%d chars)", name, len(data))
+    return data
+
+
+def available() -> list:
+    """List available layout names."""
+    layouts = []
+    for f in os.listdir(_LAYOUT_DIR):
+        if f.endswith(".json"):
+            layouts.append(f[:-5])
+    return sorted(layouts)