feat: complete Issue #150 - Advanced Packaging Features (.mdz, .mdt)

Implement comprehensive advanced packaging system using complete TDD8 methodology:

## Core Features Delivered
- **MDZ Format**: Self-contained ZIP packages with embedded assets and metadata
- **Transclusion Engine**: Dynamic content inclusion with variables and conditionals
- **Asset Management**: Automated discovery, integrity validation, and path rewriting
- **Variant Integration**: Seamless integration with existing explode-implode system

## Technical Implementation
- **53 comprehensive tests** with 100% coverage for new functionality
- **Circular import resolution** using lazy loading pattern in variant factory
- **Cross-platform compatibility** with proper path handling
- **Robust error handling** with specialized exception hierarchy

## Quality Assurance
- ✅ All 1798 tests passing (100% system compatibility maintained)
- ✅ Complete documentation (user guide + API reference)
- ✅ Working demonstration script showcasing all features
- ✅ Zero breaking changes to existing functionality

## Files Added/Modified
- **Core Implementation**: 17 new files (4,149+ lines)
- **Documentation**: Complete user and API documentation
- **Tests**: 53 new tests across 3 test modules
- **Integration**: Enhanced variant factory with MDZ support

Built on solid foundation from Issues #148-149. Production-ready with
comprehensive test coverage and full backward compatibility.

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

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

markitect/packaging/transclusion/directives.py

@@ -0,0 +1,176 @@
+"""
+Transclusion directive parsing.
+
+Provides parsers and handlers for various transclusion directives
+including file inclusion, variable substitution, and conditional content.
+"""
+
+import re
+from typing import Dict, Any, Optional, Tuple, List
+from dataclasses import dataclass
+
+
+@dataclass
+class Directive:
+    """Represents a parsed transclusion directive."""
+    type: str
+    args: Dict[str, Any]
+    content: Optional[str] = None
+    start_pos: int = 0
+    end_pos: int = 0
+
+
+class DirectiveParser:
+    """
+    Parser for transclusion directives in markdown content.
+
+    Supports various directive types including file inclusion,
+    variable substitution, and conditional content processing.
+    """
+
+    # Directive patterns
+    INCLUDE_PATTERN = re.compile(r'\{\{\s*include\s+"([^"]+)"\s*\}\}', re.IGNORECASE)
+    INCLUDE_WITH_ARGS_PATTERN = re.compile(
+        r'\{\{\s*include\s+"([^"]+)"\s+(.+?)\s*\}\}', re.IGNORECASE
+    )
+    VARIABLE_PATTERN = re.compile(r'\{\{\s*([a-zA-Z_][a-zA-Z0-9_]*)\s*\}\}')
+    CONDITIONAL_BLOCK_PATTERN = re.compile(
+        r'\{\{\s*if\s+([^}]+)\s*\}\}(.*?)\{\{\s*endif\s*\}\}',
+        re.DOTALL | re.IGNORECASE
+    )
+
+    @classmethod
+    def parse_directives(cls, content: str) -> List[Directive]:
+        """
+        Parse all directives from content.
+
+        Args:
+            content: Content to parse
+
+        Returns:
+            List of parsed directives
+        """
+        directives = []
+
+        # Parse include directives with arguments
+        for match in cls.INCLUDE_WITH_ARGS_PATTERN.finditer(content):
+            file_path = match.group(1)
+            args_str = match.group(2)
+            args = cls._parse_directive_args(args_str)
+            args['file'] = file_path
+
+            directives.append(Directive(
+                type='include',
+                args=args,
+                start_pos=match.start(),
+                end_pos=match.end()
+            ))
+
+        # Parse simple include directives
+        for match in cls.INCLUDE_PATTERN.finditer(content):
+            # Skip if already parsed as include with args
+            if any(d.start_pos <= match.start() < d.end_pos for d in directives):
+                continue
+
+            file_path = match.group(1)
+
+            directives.append(Directive(
+                type='include',
+                args={'file': file_path},
+                start_pos=match.start(),
+                end_pos=match.end()
+            ))
+
+        # Parse variable references
+        for match in cls.VARIABLE_PATTERN.finditer(content):
+            # Skip if inside other directives
+            if any(d.start_pos <= match.start() < d.end_pos for d in directives):
+                continue
+
+            var_name = match.group(1)
+
+            directives.append(Directive(
+                type='variable',
+                args={'name': var_name},
+                start_pos=match.start(),
+                end_pos=match.end()
+            ))
+
+        # Parse conditional blocks
+        for match in cls.CONDITIONAL_BLOCK_PATTERN.finditer(content):
+            condition = match.group(1)
+            block_content = match.group(2)
+
+            directives.append(Directive(
+                type='conditional',
+                args={'condition': condition},
+                content=block_content,
+                start_pos=match.start(),
+                end_pos=match.end()
+            ))
+
+        # Sort by position to process in order
+        directives.sort(key=lambda d: d.start_pos)
+
+        return directives
+
+    @classmethod
+    def _parse_directive_args(cls, args_str: str) -> Dict[str, Any]:
+        """
+        Parse directive arguments string.
+
+        Args:
+            args_str: Arguments string to parse
+
+        Returns:
+            Dictionary of parsed arguments
+        """
+        args = {}
+
+        # Simple key=value parsing
+        for part in args_str.split():
+            if '=' in part:
+                key, value = part.split('=', 1)
+                # Remove quotes if present
+                if value.startswith('"') and value.endswith('"'):
+                    value = value[1:-1]
+                elif value.startswith("'") and value.endswith("'"):
+                    value = value[1:-1]
+
+                # Try to convert to appropriate type
+                if value.lower() in ('true', 'false'):
+                    value = value.lower() == 'true'
+                elif value.isdigit():
+                    value = int(value)
+                else:
+                    try:
+                        value = float(value)
+                    except ValueError:
+                        pass  # Keep as string
+
+                args[key] = value
+
+        return args
+
+    @classmethod
+    def extract_file_includes(cls, content: str) -> List[str]:
+        """
+        Extract all file paths from include directives.
+
+        Args:
+            content: Content to analyze
+
+        Returns:
+            List of file paths referenced in include directives
+        """
+        files = []
+
+        # Extract from simple includes
+        for match in cls.INCLUDE_PATTERN.finditer(content):
+            files.append(match.group(1))
+
+        # Extract from includes with args
+        for match in cls.INCLUDE_WITH_ARGS_PATTERN.finditer(content):
+            files.append(match.group(1))
+
+        return files