Complete MZTC build blockers exposed by enabling USE_MZTC in SITL

Enabling the feature in SITL (previous commit) surfaced two latent
issues in the feature code that only manifest when USE_MZTC is actually
compiled in:

- mztc_camera.c used fprintf(stderr, ...) via the SD() macro without
  including <stdio.h> (6 'stderr undeclared' compile errors).
- mztc_camera_osd.c declared mztcOsdConfig via PG_DECLARE and used
  PG_MZTC_OSD_CONFIG (1047) but never registered the parameter group
  (undefined reference to mztcOsdConfig_System at link time). Added
  PG_REGISTER_WITH_RESET_TEMPLATE + PG_RESET_TEMPLATE following the
  mztcConfig pattern, with the MZTC_OSD_DEFAULT_* defines moved above
  the template so the macros resolve.

SITL now compiles and links with the camera code active (verified via
fresh cmake -DSITL=ON + make SITL build).

Author: sensei-hacker

src/main/io/mztc_camera.c

@@ -17,6 +17,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <stdio.h>
 #include <string.h>
 #include <math.h>
 #include <stdlib.h>

src/main/io/osd/mztc_camera_osd.c

@@ -40,8 +40,6 @@
 
 #ifdef USE_MZTC
 
-// Parameter group ID for MassZero Thermal Camera OSD configuration (defined in parameter_group_ids.h)
-
 // Default OSD configuration values
 #define MZTC_OSD_DEFAULT_ENABLED        1
 #define MZTC_OSD_DEFAULT_TEMP_DISPLAY   1
@@ -53,6 +51,21 @@
 #define MZTC_OSD_DEFAULT_POS_Y          10
 #define MZTC_OSD_DEFAULT_VISIBILITY     MZTC_OSD_VISIBLE_ALWAYS
 
+// Parameter group for MassZero Thermal Camera OSD configuration
+PG_REGISTER_WITH_RESET_TEMPLATE(mztcOsdConfig_t, mztcOsdConfig, PG_MZTC_OSD_CONFIG, 0);
+
+PG_RESET_TEMPLATE(mztcOsdConfig_t, mztcOsdConfig,
+    .enabled = MZTC_OSD_DEFAULT_ENABLED,
+    .temperature_display = MZTC_OSD_DEFAULT_TEMP_DISPLAY,
+    .status_display = MZTC_OSD_DEFAULT_STATUS_DISPLAY,
+    .alerts_display = MZTC_OSD_DEFAULT_ALERTS_DISPLAY,
+    .calibration_display = MZTC_OSD_DEFAULT_CALIB_DISPLAY,
+    .connection_display = MZTC_OSD_DEFAULT_CONN_DISPLAY,
+    .position_x = MZTC_OSD_DEFAULT_POS_X,
+    .position_y = MZTC_OSD_DEFAULT_POS_Y,
+    .visibility_flags = MZTC_OSD_DEFAULT_VISIBILITY,
+);
+
 
 // Internal state
 static bool mztcOsdInitialized = false;