refactor(gdb): use pygdbmi for MI communication and fix symbol resolution

- Replace hand-written GDB/MI parser with pygdbmi IoManager
- Auto-start GDB session on WebServer startup when ELF is configured
- Fix address parsing for 'is at 0x...' format (no-debug symbols)
- Strip array suffix from symbol names before GDB queries
- Add linker-name fallback for scoped C++ symbols (sizeof/ptype)
- Log raw GDB output on parse failures for easier debugging
- Add pygdbmi to requirements.txt

Author: FASTSHIFT