Add SD SPI CMD13 status response

docs/tec1g-emulation-review.md

@@ -756,6 +756,7 @@ External add-on emulation. Fully independent of other stages.
 - [x] CMD58 (READ_OCR): respond with OCR register
 - [x] CMD17 (READ_SINGLE_BLOCK): respond with data token + 512 bytes from virtual image
 - [x] CMD24 (WRITE_SINGLE_BLOCK): accept data token + 512 bytes and write into virtual image
+- [x] CMD13 (SEND_STATUS): respond with R2 status bytes
 - [x] Unit tests: full initialization sequence (CMD0 -> CMD8 -> ACMD41 -> CMD58)
 
 #### 6C — SD card integration with runtime

src/platforms/tec1g/sd-spi.ts

@@ -254,6 +254,12 @@ export class SdSpi {
         this.delayBytes = 1;
         break;
       }
+      case 13: {
+        const r1 = this.ready ? 0x00 : 0x01;
+        this.pendingResponse = [r1, 0x00];
+        this.delayBytes = 1;
+        break;
+      }
       case 17: {
         if (!this.ready) {
           this.pendingResponse = [0x01];

tests/platforms/tec1g/sd-spi.test.ts

@@ -178,4 +178,28 @@ describe('SdSpi', () => {
     expect(image[1]).toBe(0x34);
     expect(image[2]).toBe(0x56);
   });
+
+  it('responds to CMD13 with status', () => {
+    const spi = new SdSpi({ csMask: CS_BIT });
+    writeSpi(spi, 0x00);
+    sendCommand(spi, [0x77, 0x00, 0x00, 0x00, 0x00, 0x65]);
+    readResponseByte(spi);
+    sendCommand(spi, [0x69, 0x40, 0x00, 0x00, 0x00, 0x77]);
+    readResponseByte(spi);
+    sendCommand(spi, [0x77, 0x00, 0x00, 0x00, 0x00, 0x65]);
+    readResponseByte(spi);
+    sendCommand(spi, [0x69, 0x40, 0x00, 0x00, 0x00, 0x77]);
+    readResponseByte(spi);
+    sendCommand(spi, [0x4d, 0x00, 0x00, 0x00, 0x00, 0xff]);
+    expect(readResponseByte(spi)).toBe(0x00);
+    expect(readByte(spi)).toBe(0x00);
+  });
+
+  it('returns idle status for CMD13 before init', () => {
+    const spi = new SdSpi({ csMask: CS_BIT });
+    writeSpi(spi, 0x00);
+    sendCommand(spi, [0x4d, 0x00, 0x00, 0x00, 0x00, 0xff]);
+    expect(readResponseByte(spi)).toBe(0x01);
+    expect(readByte(spi)).toBe(0x00);
+  });
 });