feat(patterns): driver_patterns helper, on/off ota guard, drop duplicate py tree

Made-with: Cursor

src/util/driver_patterns.py

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+import os
+
+_ENV_PATTERNS_DIR = "LED_CONTROLLER_PATTERNS_DIR"
+
+def driver_patterns_dir():
+    """Absolute path to driver pattern ``.py`` modules.
+
+    If ``LED_CONTROLLER_PATTERNS_DIR`` is set to an existing directory, that wins
+    (for installs where ``led-driver`` is not next to this repo). Otherwise uses
+    ``<project-root>/led-driver/src/patterns``.
+    """
+    env = (os.environ.get(_ENV_PATTERNS_DIR) or "").strip()
+    if env and os.path.isdir(env):
+        return os.path.abspath(env)
+    here = os.path.dirname(os.path.abspath(__file__))
+    root = os.path.abspath(os.path.join(here, "..", ".."))
+    return os.path.join(root, "led-driver", "src", "patterns")
+
+
+def normalize_pattern_py_filename(name):
+    """Return a single ``*.py`` basename (no paths), or ``\"\"`` if invalid.
+
+    Strips repeated ``.py`` suffixes so ``blink.py.py`` becomes ``blink.py``.
+    """
+    if not isinstance(name, str):
+        return ""
+    s = name.strip()
+    if not s:
+        return ""
+    lower = s.lower()
+    while lower.endswith(".py"):
+        s = s[:-3]
+        s = s.strip()
+        lower = s.lower()
+    if not s:
+        return ""
+    if "/" in s or "\\" in s or ".." in s:
+        return ""
+    return s + ".py"
+
+
+# Implemented in led-driver ``presets.py`` only — no separate ``patterns/*.py``.
+FIRMWARE_BUILTIN_PATTERN_IDS = frozenset({"on", "off"})
+
+
+def is_firmware_builtin_pattern_module(name):
+    """True for ``on`` / ``off``, with or without a ``.py`` suffix."""
+    if not isinstance(name, str):
+        return False
+    s = name.strip().lower()
+    while s.endswith(".py"):
+        s = s[:-3].strip()
+    return s in FIRMWARE_BUILTIN_PATTERN_IDS