Improve error handling, validation and code quality

Applied fixes for issues #2, #3, #4 and medium priority improvements:

**Issue #2: Add preg_match() validation in Short converter**
- src/Converter/Short.php: Check preg_match return value before using matches
- Throw descriptive RuntimeException if hex format is invalid

**Issue #3: Add descriptive exception messages to Reverser classes**
- src/Reverser/ReverseBinary.php: Add error message with actual byte length
- src/Reverser/ReverseHex.php: Add error message showing expected vs actual format
- src/Reverser/ReverseShortened.php: Add error message for full-length UUID rejection

**Issue #4: Fix misleading PHPDoc in ExposeBehavior**
- src/Model/Behavior/ExposeBehavior.php: Remove incorrect @throws tag about 'slug' key
- The method signature already shows it takes string $uuid directly

**Medium #1: Add file validation for migration command**
- src/Command/AddExposedFieldCommand.php: Validate migration path exists and is writable
- Add error handling for file_put_contents() failure

**Medium #3: Improve error message in ExposeBehavior**
- src/Model/Behavior/ExposeBehavior.php: Show actual column type in error message
- Helps debugging when column type cannot be determined

**Medium #6: Document SuperimposeComponent config**
- src/Controller/Component/SuperimposeComponent.php: Add inline comment explaining actions array

All changes improve error handling, make debugging easier, and prevent
potential bugs from unchecked return values.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: dereuromark

src/Command/AddExposedFieldCommand.php

@@ -101,7 +101,16 @@ public function execute(Arguments $args, ConsoleIo $io): ?int {
 			if ($this->migrationExists($migrationName, $this->migrationPath)) {
 				$io->abort('File already exists: ' . $migrationFilePath);
 			}
-			file_put_contents($migrationFilePath, $migrationContent);
+			if (!is_dir($this->migrationPath)) {
+				$io->abort('Migration path does not exist: ' . $this->migrationPath);
+			}
+			if (!is_writable($this->migrationPath)) {
+				$io->abort('Migration path is not writable: ' . $this->migrationPath);
+			}
+			$bytesWritten = @file_put_contents($migrationFilePath, $migrationContent);
+			if ($bytesWritten === false) {
+				$io->abort('Failed to write migration file: ' . $migrationFilePath);
+			}
 			$io->success('Migration file created. Now you can migrate your table(s) using `bin/cake migrations migrate`.');
 		} else {
 			$io->out('--- ' . $migrationName . '.php' . ' ---');

src/Controller/Component/SuperimposeComponent.php

@@ -16,7 +16,7 @@ class SuperimposeComponent extends Component {
 	 * @var array<string, mixed>
 	 */
 	protected array $_defaultConfig = [
-		'actions' => [],
+		'actions' => [], // Array of action names (strings) to apply superimposition to
 	];
 
 	/**

src/Converter/Short.php

@@ -109,7 +109,10 @@ protected function stringToNum(string $string): BigInteger {
 	 */
 	protected function formatHex(string $hex): string {
 		$hex = str_pad($hex, 32, '0');
-		preg_match('/([a-f0-9]{8})([a-f0-9]{4})([a-f0-9]{4})([a-f0-9]{4})([a-f0-9]{12})/', $hex, $matches);
+		$matched = preg_match('/([a-f0-9]{8})([a-f0-9]{4})([a-f0-9]{4})([a-f0-9]{4})([a-f0-9]{12})/', $hex, $matches);
+		if ($matched === 0) {
+			throw new RuntimeException('Invalid hex string format: ' . $hex);
+		}
 		array_shift($matches);
 
 		return implode('-', $matches);

src/Model/Behavior/ExposeBehavior.php

@@ -93,7 +93,6 @@ public function getExposedKey(bool $prefixed = false): string {
 	 *
 	 * @param \Cake\ORM\Query\SelectQuery $query
 	 * @param string $uuid
-	 * @throws \InvalidArgumentException If the 'slug' key is missing in options
 	 * @return \Cake\ORM\Query\SelectQuery
 	 */
 	public function findExposed(SelectQuery $query, string $uuid): SelectQuery {
@@ -205,7 +204,9 @@ public function initExposedField(array $params = []): int {
 	protected function generateExposedField(string $field): string {
 		$fieldType = $this->_table->getSchema()->getColumnType($field);
 		if (!$fieldType) {
-			throw new RuntimeException('Cannot determine column type of field `' . $field . '`');
+			$schema = $this->_table->getSchema()->getColumn($field);
+
+			throw new RuntimeException('Cannot determine column type of field `' . $field . '`. Found type: ' . ($schema['type'] ?? 'unknown'));
 		}
 
 		$type = TypeFactory::build($fieldType);

src/Reverser/ReverseBinary.php

@@ -13,7 +13,7 @@ class ReverseBinary implements ReverseStrategyInterface {
 	 */
 	public function reverse(string $uuid): string {
 		if (strlen($uuid) !== 16) {
-			throw new RuntimeException();
+			throw new RuntimeException('Expected 16-byte binary UUID, got ' . strlen($uuid) . ' bytes');
 		}
 
 		return (string)(new BinaryUuidType())->toPHP($uuid, new Mysql());

src/Reverser/ReverseHex.php

@@ -18,7 +18,7 @@ public function reverse(string $uuid): string {
 			return (string)(new BinaryUuidType())->toPHP($binaryUuid, new Mysql());
 		}
 
-		throw new RuntimeException();
+		throw new RuntimeException('Expected hex format starting with "0x" and length 34, got: ' . $uuid);
 	}
 
 }

src/Reverser/ReverseShortened.php

@@ -12,7 +12,7 @@ class ReverseShortened implements ReverseStrategyInterface {
 	 */
 	public function reverse(string $uuid): string {
 		if (strlen($uuid) === 36) {
-			throw new RuntimeException();
+			throw new RuntimeException('Cannot reverse full-length UUID (36 chars), expected shortened format');
 		}
 
 		return ConverterFactory::getConverter()->decode($uuid);