halxx: address review, add master compatibility

- Include <hal.h> globally, not locally
- Use rtapi_ type names throughout (rtapi_bool/s32/u32/sint/uint/real)
  so the layer follows the rtapi abstraction
- pin/port/anypin are move-only (HAL objects are unique, no refcounting)
- Query callbacks are strictly exception-free: convert_value reports
  range errors by flag, callers throw after the library releases the
  HAL mutex
- Namespace linuxcnc::hal (IniFile convention), compat aliases kept
- hal_malloc(sizeof(*u)) style
- Gate the by-name query API section on the query API's public marker
  (COMPONENT_TYPE_* macros) so the typed layer also compiles against
  master without the query API; hal_strerror has a fallback
- Port documented as FIFO endpoint pair, transitional handle noted

Author: grandixximo