refactor: restructure core modules into context and memory packages

- Move pm_init components to dedicated packages
- context/: PM mode initialization and contracts
- memory/: Reflexion memory system
- Remove deprecated superclaude/core/pm_init/

Breaking change: Import paths updated
- Old: superclaude.core.pm_init.context_contract
- New: superclaude.context.contract

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

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

superclaude/memory/__init__.py

@@ -0,0 +1,11 @@
+"""Learning and Memory Systems
+
+Manages long-term learning from experience:
+- Reflexion Memory (mistake learning)
+- Metrics collection
+- Pattern recognition
+"""
+
+from .reflexion import ReflexionMemory, ReflexionEntry
+
+__all__ = ["ReflexionMemory", "ReflexionEntry"]