修复调色板 BGR/RGB 顺序：render 输出标准 RGB24（官方 palette 为 BGR 存储）

- mag160c_render_frame 之前把 palette[gv][0]=B 直接写入 out_rgb[0]，
  导致 R/B 互换，高温区域显示为蓝色
- 改为 out_rgb = {palette[2], palette[1], palette[0]} 标准 RGB24
- linux_demo 的 BMP 输出相应改为写回 BGR（BMP 原生顺序）
- 实测：最热像素 (255,255,150) 亮黄白，低温区域蓝黑，色温方向正确

csdk/src/mag160c_render.c

@@ -626,12 +626,12 @@ mag160c_error_t mag160c_render_frame(mag160c_render_t *r, const uint8_t *frame,
     if (r->post_gray_cb)
         r->post_gray_cb(r->post_gray_user, r->gray160);
     upscale2x(r);
-    /* palette colorize 320x240 */
+    /* palette colorize 320x240 (palette is B,G,R -> swap to RGB24 out) */
     for (int i = 0; i < r->npix * 4; ++i) {
         unsigned char gv = r->gray320[i];
-        out_rgb[i * 3 + 0] = mag160c_official_palette256[gv][0];
+        out_rgb[i * 3 + 0] = mag160c_official_palette256[gv][2];
         out_rgb[i * 3 + 1] = mag160c_official_palette256[gv][1];
-        out_rgb[i * 3 + 2] = mag160c_official_palette256[gv][2];
+        out_rgb[i * 3 + 2] = mag160c_official_palette256[gv][0];
     }
     return MAG160C_OK;
 }

csdk/tools/mag160c_linux_demo.c

@@ -102,8 +102,13 @@ static void save_bmp(const char *path, const uint8_t *rgb, int w, int h) {
     FILE *f = fopen(path, "wb");
     if (!f) return;
     fwrite(bmp, 1, 54, f);
-    for (int y = h - 1; y >= 0; --y)
+    for (int y = h - 1; y >= 0; --y) {
-        fwrite(rgb + (size_t)y * w * 3, 1, (size_t)w * 3, f);
+        const uint8_t *row = rgb + (size_t)y * w * 3;
+        for (int x = 0; x < w; ++x) {
+            uint8_t bgr[3] = { row[x * 3 + 2], row[x * 3 + 1], row[x * 3] };
+            fwrite(bgr, 1, 3, f);
+        }
+    }
     fclose(f);
 }