Add StringContainsAny node for conditional workflows (Issue #9)

New node checks if input string contains any of multiple substrings,
returning a boolean and the first matched string. Useful for conditionally
loading LoRAs based on prompt keywords.

string_contains_any_node.py

@@ -0,0 +1,52 @@
+class StringContainsAnyNode:
+    """Check if an input string contains any of multiple substrings."""
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "input_string": ("STRING", {
+                    "forceInput": True,
+                    "tooltip": "The string to search within"
+                }),
+                "substrings": ("STRING", {
+                    "multiline": True,
+                    "default": "",
+                    "placeholder": "Enter substrings to search for (one per line)",
+                    "tooltip": "Enter substrings to check (one per line). Returns true if ANY are found."
+                }),
+                "match_case": ("BOOLEAN", {
+                    "default": False,
+                    "label_on": "enabled",
+                    "label_off": "disabled",
+                    "tooltip": "Whether the search should be case-sensitive"
+                })
+            }
+        }
+
+    RETURN_TYPES = ("BOOLEAN", "STRING")
+    RETURN_NAMES = ("contains_any", "matched_string")
+    FUNCTION = "contains_any"
+    CATEGORY = "utils/StringEssentials"
+
+    def contains_any(self, input_string, substrings, match_case):
+        # Parse substrings, one per line
+        substrings_list = []
+        for line in substrings.splitlines():
+            line = line.strip()
+            if line:
+                substrings_list.append(line)
+
+        if not substrings_list:
+            return (False, "")
+
+        # Prepare strings for comparison
+        search_string = input_string if match_case else input_string.lower()
+
+        # Check each substring
+        for substring in substrings_list:
+            check_substring = substring if match_case else substring.lower()
+            if check_substring in search_string:
+                return (True, substring)
+
+        return (False, "")