Worker thread for crawling.

**Flow**: Poll URL → Validate → Get client → Delay → Check last-modified → Execute → Process → Extract children → Queue children → Delay

### CrawlerClientFactory

Pattern-based client selection using `LinkedHashMap<Pattern, CrawlerClient>`.

**Standard Patterns**:
```java
"^https?://.*"     → httpClient
"^file:.*"         → fileSystemClient
"^ftp://.*"        → ftpClient
"^smb://.*"        → smbClient

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;
import java.util.regex.Pattern;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.fess.opensearch.log.bsbhv.BsFavoriteLogBhv;
import org.codelibs.fess.util.ComponentUtil;

    public static Map<String, String> parse(final String value) {
        final Map<String, String> paramMap = new LinkedHashMap<>();
        if (value != null) {
            int unknownKey = 0;
            final Pattern properyPattern = Pattern.compile(ComponentUtil.getFessConfig().getAppEncryptPropertyPattern());
            final PrimaryCipher cipher = ComponentUtil.getPrimaryCipher();
            final String[] lines = value.split("[\r\n]");

**To Reproduce**
Steps to reproduce the behavior:
1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

**Expected behavior**
A clear and concise description of what you expected to happen.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Environment (please complete the following information):**
 - OS: [e.g. Windows 10]
 - Browser [e.g. chrome, safari]

     * @param in the input stream to read the mapping data from
     */
    protected void reload(final MappingUpdater updater, final InputStream in) {
        final Pattern parsePattern = Pattern.compile("(.*?)\\s*+=>\\s*+(.*?)\\s*+$");
        final List<CharMappingItem> itemList = new ArrayList<>();
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(in, Constants.UTF_8))) {

 */

import java.util.ArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Utility class for parsing CSV text
 */
public final class KuromojiCSVUtil {
    private static final char QUOTE = '"';

    private static final char COMMA = ',';

    private static final Pattern QUOTE_REPLACE_PATTERN = Pattern.compile("^\"([^\"]+)\"$");

    private static final String ESCAPED_QUOTE = "\"\"";

User-agent: SameLengthBot
Disallow: /page
Allow: /page

# Test multiple wildcards
User-agent: MultiWildcardBot
Disallow: /*.cgi*
Disallow: /*?*id=*

# Test literal $ in middle of pattern
User-agent: DollarBot
Disallow: /price$info

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.opensearch.config.exbhv;

import java.util.regex.Pattern;

import org.codelibs.fess.opensearch.config.bsbhv.BsBadWordBhv;
import org.codelibs.fess.util.ComponentUtil;

/**
 * @author FreeGen
 */
public class BadWordBhv extends BsBadWordBhv {

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.opensearch.config.exbhv;

import java.util.regex.Pattern;

import org.codelibs.fess.opensearch.config.bsbhv.BsFailureUrlBhv;
import org.codelibs.fess.util.ComponentUtil;

/**
 * @author FreeGen
 */
public class FailureUrlBhv extends BsFailureUrlBhv {

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.opensearch.config.exbhv;

import java.util.regex.Pattern;

import org.codelibs.fess.opensearch.config.bsbhv.BsFileAuthenticationBhv;
import org.codelibs.fess.util.ComponentUtil;

/**
 * @author FreeGen
 */