fix(core): escape brackets and whitespace to prevent runtime regex crashes

Resolved two critical escaping flaws in RegexEscaper that caused runtime failures:

- Added '[' to inside-bracket escaping to prevent 'Unclosed character class' PatternSyntaxException.
- Added space (' ') and hash ('#') to general escaping to safely support the COMMENTS (?x) global flag.
- Updated assertions in affected unit tests to reflect the new, safer escaped string outputs.

Author: Mirkoddd

sift-core/src/main/java/com/mirkoddd/sift/core/RegexEscaper.java

@@ -24,7 +24,7 @@ final class RegexEscaper {
     private static final boolean[] SPECIAL_CHAR_TABLE = new boolean[128];
 
     static {
-        String specialChars = ".?*+^$[](){}|\\<>=!";
+        String specialChars = ".?*+^$[](){}|\\<>=! #";
         for (char c : specialChars.toCharArray()) {
             SPECIAL_CHAR_TABLE[c] = true;
         }
@@ -67,6 +67,7 @@ static void escapeInsideBrackets(char c, StringBuilder sb) {
             case '-':
             case '^':
             case ']':
+            case '[':
             case '&': // Safety against "&&" (intersection)
                 sb.append('\\');
                 break;

sift-core/src/test/java/com/mirkoddd/sift/core/RegexEscaperTest.java

@@ -55,19 +55,19 @@ void testEscapeString_NormalCharactersAreNotEscaped() {
 
         RegexEscaper.escapeString(normalText, sb);
 
-        assertEquals("abc123 ", sb.toString());
+        assertEquals("abc123\\ ", sb.toString());
     }
 
     @Test
     void testEscapeInsideBrackets_HitsAllSpecialCharacters() {
-        char[] bracketSpecials = {'\\', '-', '^', ']', '&'};
+        char[] bracketSpecials = {'\\', '-', '^', ']', '[', '&'};
         StringBuilder sb = new StringBuilder();
 
         for (char c : bracketSpecials) {
             RegexEscaper.escapeInsideBrackets(c, sb);
         }
 
-        assertEquals("\\\\\\-\\^\\]\\&", sb.toString());
+        assertEquals("\\\\\\-\\^\\]\\[\\&", sb.toString());
     }
 
     @Test
@@ -86,6 +86,6 @@ void testEscapeInsideBrackets_NormalCharactersAreNotEscaped() {
     void literalWithNonAsciiCharacters() {
         SiftPattern pattern = SiftPatterns.literal("Caffè €");
 
-        assertEquals("Caffè €", pattern.shake());
+        assertEquals("Caffè\\ €", pattern.shake());
     }
 }

sift-core/src/test/java/com/mirkoddd/sift/core/SiftTest.java

@@ -419,7 +419,7 @@ void namedCapturing() {
                     .namedCapture(orderIdGroup)
                     .shake();
 
-            assertEquals("Order: #(?<orderId>[0-9]+)", regex);
+            assertEquals("Order:\\ \\#(?<orderId>[0-9]+)", regex);
 
             Matcher m = Pattern.compile(regex).matcher("Status for Order: #9988");
             assertTrue(m.find());
@@ -1019,7 +1019,7 @@ void positiveLookbehindTest() {
                     .pattern(literal("apple"))
                     .shake();
 
-            assertEquals("(?<=green )apple", regex);
+            assertEquals("(?<=green\\ )apple", regex);
             assertRegexMatches(regex, "I like my green apple.");
             assertRegexDoesNotMatch(regex, "I like my red apple.");
         }