refactor(printer): replace direct_printer with printer naming

README.md

@@ -6,7 +6,7 @@ business REST endpoints (`/v1/*`).
 ## Features
 
 - Thermal printer driver (single printer path)
-- Auto-connect printer during startup
+- Auto-initialize printer driver during startup
 - Async print queue and worker lifecycle management
 - Printer precheck (paper / battery / temperature)
 - MIC key push-to-talk voice flow (button-triggered, no HTTP trigger)
@@ -52,7 +52,6 @@ In `menuconfig -> TQ Printer Config`:
   - `TQ_WIFI_PROV_SOFTAP_CHANNEL`
   - `TQ_WIFI_PROV_SOFTAP_MAX_CONN`
 - Thermal printer runtime and safety policy:
-  - `TQ_DIRECT_PRINTER_*`
   - `TQ_PRINTER_*`
 - Z-Image HTTP fields:
   - `TQ_Z_IMAGE_API_KEY` (optional, empty means fallback to `TQ_VOICE_API_KEY`)