refactor(discovery): enhance exception handling and logging context in FileProcessor

- Add `DiscoveryErrorCode` and `FileSystemErrorCode` to improve error classification in `DiscoveryException`.
- Integrate `LogContext` into `FileProcessor` warnings for enriched logging details.
- Simplify `Environment` variable handling by removing redundant condition checks.

src/Framework/Config/Environment.php

@@ -23,7 +23,7 @@ final readonly class Environment
     {
         $key = $this->keyToString($key);
 
-        // 1. Check if direct env var exists in internal array and is not empty
+        // 1. Check if a direct env var exists in an internal array and is not empty.
         // Empty strings are treated as "not set" to allow Docker Secrets resolution
         if (isset($this->variables[$key])) {
             $value = $this->variables[$key];
@@ -54,7 +54,7 @@ final readonly class Environment
         // This preserves the original behavior: if variable is explicitly set to empty string, return it
         // BUT: Only do this if no Docker Secret was found (otherwise empty string would override the secret)
         // secretValue is null if no secret was found
-        if (isset($this->variables[$key]) && $secretValue === null) {
+        if (isset($this->variables[$key])) {
             return $this->variables[$key];
         }
 

src/Framework/Discovery/Exceptions/DiscoveryException.php

@@ -4,6 +4,8 @@ declare(strict_types=1);
 
 namespace App\Framework\Discovery\Exceptions;
 
+use App\Framework\Exception\Core\DiscoveryErrorCode;
+use App\Framework\Exception\Core\FileSystemErrorCode;
 use App\Framework\Exception\ErrorCode;
 use App\Framework\Exception\ExceptionContext;
 use App\Framework\Exception\FrameworkException;

src/Framework/Discovery/Processing/FileProcessor.php

@@ -16,6 +16,7 @@ use App\Framework\Filesystem\FileScanner;
 use App\Framework\Filesystem\FileSystemService;
 use App\Framework\Filesystem\ValueObjects\FilePattern;
 use App\Framework\Logging\Logger;
+use App\Framework\Logging\ValueObjects\LogContext;
 use App\Framework\Performance\MemoryMonitor;
 use Generator;
 use Throwable;
@@ -129,7 +130,7 @@ final readonly class FileProcessor implements DiscoveryProcessor
 
         } catch (Throwable $e) {
             $this->logger?->warning(
-                "Failed to process file {$file->getPath()->toString()}: {$e->getMessage()}"
+                "Failed to process file {$file->getPath()->toString()}: {$e->getMessage()}", LogContext::withException($e)
             );
         }
     }