Find the longest common prefix string among a list of strings. If there is no common prefix, return an empty string. Comparison should be case-sensitive. Return an empty string for null or empty input lists.

Method Signature:

public static String findLongestCommonPrefix(List<String> strings)

Examples:

List<String> strings = new List<String>{ 'flower', 'flow', 'flight' };
String result = findLongestCommonPrefix(strings);
// Result: 'fl'
// Explanation: The common prefix is 'fl'

List<String> strings = new List<String>{ 'dog', 'racecar', 'car' };
String result = findLongestCommonPrefix(strings);
// Result: ''
// Explanation: No common prefix exists

List<String> strings = new List<String>{ 'test', 'testing', 'tester' };
String result = findLongestCommonPrefix(strings);
// Result: 'test'
// Explanation: All strings start with 'test'

List<String> strings = new List<String>();
String result = findLongestCommonPrefix(strings);
// Result: ''
// Explanation: Empty list returns empty string

List<String> strings = new List<String>{ 'apple' };
String result = findLongestCommonPrefix(strings);
// Result: 'apple'
// Explanation: Single string returns itself
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