feat: implement MemoryStore with address-based access

- Add IMemoryStore interface with Read/Write/Export/Import methods
- Add MemoryStore implementation aggregating all memory regions
- Support S7 address formats: M100, DB1.DBD0, I0.0, Q0.0, T1, C1
- Add type-safe read/write for basic types (short, int, ushort, float, bool)
- Add memory export/import functionality

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>