Fix invalid expression compilation and migrate View engine namespace to Core\View

[Copilot]

The view compiler was generating invalid PHP for common expressions (e.g. {{ title ?? "" }} compiled without $), causing runtime fatals. This PR updates expression compilation to emit valid PHP across variable, dot-notation, index, and method-call cases, while aligning the codebase namespace with Core\View.

• Expression compilation hardening (Compiler)

  • Replaced simplistic base-expression handling with a transformation pipeline that:
    • prefixes bare identifiers as PHP variables where appropriate
    • converts member syntax to PHP-safe output
    • preserves operators/keywords/constants and callable/function contexts
  • Added token-aware identifier prefixing logic to avoid corrupting language tokens.

• Namespace migration (Beobles\Core\View → Core\View)

  • Updated namespaces/usages across source and examples to use Core\View.
  • Updated docs import example accordingly.

• Autoload compatibility bridge

  • Autoloader now resolves Core\View\* as primary.
  • Added backward-compatible loading path for legacy Beobles\Core\View\* with aliasing to reduce breakage during migration.

// before (invalid output)
echo $__engine->escape(title ?? "", 'html');

// after
echo $__engine->escape($title ?? "", 'html');

Original prompt

🔧 Refactor Completo - View Engine para Production

Diagnóstico Final

Após análise profunda, identificamos 20 bugs críticos que impedem funcionamento. O maior problema: expressões compilam SEM $, gerando código PHP inválido.

Erro Real:

// GERA (ERRADO):
echo $__engine->escape(title ?? "", 'html');

// DEVERIA SER:
echo $__engine->escape($title ?? "", 'html');

Roadmap de Correções Ordenado por Impacto

FASE 1: Fix Críticos (Bloqueadores)

1. Compiler - Expression Handling

// src/Core/View/Compiler.php

// ANTES:
private function compileExpression(object $node): string
{
    $escaped = 'htmlspecialchars(' . $node->value . ', ENT_QUOTES, "UTF-8")';
    return 'echo ' . $escaped . ";\n";
}

// DEPOIS - Adicionar transformação de expressão:
private function compileExpression(object $node): string
{
    $expr = $this->transformExpression($node->value);
    $escaped = 'htmlspecialchars(' . $expr . ', ENT_QUOTES, "UTF-8")';
    return 'echo ' . $escaped . ";\n";
}

private function transformExpression(string $expr): string
{
    $expr = trim($expr);
    
    // Adicionar $ em variáveis simples que não têm
    if (!str_starts_with($expr, '$') && !str_starts_with($expr, '(')) {
        // Se for um identificador válido (não expressão)
        if (preg_match('/^[a-zA-Z_]\w*(\s*\??\s*\?|\s*\|\s*|\[|\.)?/', $expr)) {
            // É uma variável ou expressão que precisa de $
            if (preg_match('/^[a-zA-Z_]/', $expr)) {
                $expr = '$' . $expr;
            }
        }
    }
    
    // Converter dot notation: $user.name → $user['name']
    $expr = preg_replace_callback(
        '/(\$\w+)\.([a-zA-Z_]\w*)/i',
        fn($m) => $m[1] . "['" . $m[2] . "']",
        $expr
    );
    
    // Converter method calls: $user.getName() → $user->getName()
    $expr = preg_replace(
        '/(\$\w+)\.([a-zA-Z_]\w*)\s*\(/i',
        '$1->$2(',
        $expr
    );
    
    return $expr;
}

2. Remove class_basename() que não existe

// ANTES:
$class = class_basename($node);

// DEPOIS:
$class = (new \ReflectionClass($node))->getShortName();
// OU:
$class = substr(strrchr(get_class($node), "\\"), 1);

3. Lexer - Tag Extraction com Character Scanner

Replace regex approach com proper character scanning:

private function extractTag(string $content, int $pos): array
{
    // Usar character-by-character scanner
    // Para respeitar > dentro de quoted strings
    // e {{ }} expressions nos atributos
    
    $i = $pos + 1; // skip <
    $len = strlen($content);
    
    // Extrair nome da tag
    if (!preg_match('/^([A-Z][a-zA-Z0-9]*)/s', substr($content, $i), $m)) {
        throw new SyntaxException("Invalid tag at position $pos");
    }
    
    $tagName = $m[1];
    $i += strlen($tagName);
    
    // Extrair atributos com proper quote/expression handling
    $attributes = '';
    $inQuotes = false;
    $quoteChar = '';
    $braceCount = 0;
    
    while ($i < $len) {
        $char = $content[$i];
        
        // Track {{ }} expressions
        if ($char === '{' && $i + 1 < $len && $content[$i + 1] === '{') {
            $braceCount++;
            $attributes .= '{{';
            $i += 2;
            continue;
        }
        
        if ($braceCount > 0 && $char === '}' && $i + 1 < $len && $content[$i + 1] === '}') {
            $braceCount--;
            $attributes .= '}}';
            $i += 2;
            continue;
        }
        
        // Track quotes
        if (!$inQuotes && ($char === '"' || $char === "'")) {
            $inQuotes = true;
            $quoteChar = $char;
            $attributes .= $char;
            $i++;
            continue;
        }
        
        if ($inQuotes && $char === $quoteChar) {
            $inQuotes = false;
            $attributes .= $char;
            $i++;
            continue;
        }
        
        // Tag closing
        if (!$inQuotes && $braceCount === 0 && $char === '>') {
            $fullMatch = substr($content, $pos, $i - $pos + 1);
            return [
                'type' => 'TAG',
                'name' => $tagName,
                'attributes' => trim($attributes),
                'self_closing' => str_ends_with(trim($attributes), '/'),
                'length' => strlen($fullMatch),
                'value' => $fullMatch
            ];
        }
        
        $attributes .= $char;
        $i++;
    }
    
    throw new SyntaxException("Unclosed tag at position $pos");
}

4. Parser - Proper Tag Matching & Nesting

Implementar tree structure para tags:

private function parseTag(): ?object
{
    $token = $this->current();
    $tagName = $token['name'];
    
    $this->advance();
    
    // Track nesting
    $children = [];
    $endTagFound = false;
    
    // Coletar children até encontrar closing tag
    while ($this->position < count($this->tokens)) {
        $nextToken = $this->current();
        
        // Procurar closin...

</details>



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