libptouch: P700/P900 families, optional JSON config, ESC i z and print sequencing

- Add printer_family and profile flags; load overrides from printer_families.json
- Set ESC i z page byte from profile; pass prof into ptouch_fill_esc_iz
- End print with 0x1A only (drop FF prefix); extend Ruby FFI and CLI media info
- Add reference/ptp_raster_ref.adoc; install config under share/ptouch_label

Made-with: Cursor

src/cli/main.c

@@ -124,6 +124,10 @@ static void verbose_print_pre_print_info(libptouch_ctx *ctx,
 		printf("printable dots: %u\n", (unsigned)mi.printable_dots);
 		printf("left/right margins: %u/%u dots\n",
 		       (unsigned)mi.left_margin_dots, (unsigned)mi.right_margin_dots);
+		printf("printer family: %s (%u)\n",
+		       libptouch_printer_family_label(
+			       (libptouch_printer_family_t)mi.printer_family),
+		       (unsigned)mi.printer_family);
 		printf("print/feed dpi: %.1f/%.1f\n", mi.print_dpi, mi.feed_dpi);
 	} else {
 		printf("media info: unavailable (%s)\n", libptouch_strerror(ctx));