feat(terminal): 去掉提示符/光标/输入文字的颜色

Text 默认的 prompt/cursor 由绿色改为与普通文本一致的 0xCCCCCC，
输入文字也不再硬编码白色；终端整体保持单色。

vpsdk/vpui.vp

@@ -1229,8 +1229,8 @@ virtual class Text(Widget):
         self.prompt[2] = 0
         self.bg_color = uint32(0x0C0C0C)
         self.text_color = uint32(0xCCCCCC)
-        self.prompt_color = uint32(0x00FF00)
-        self.cursor_color = uint32(0x00FF00)
+        self.prompt_color = uint32(0xCCCCCC)
+        self.cursor_color = uint32(0xCCCCCC)
         self.border_color = uint32(0x333333)
         self.on_command = None
         self.history_count = 0
@@ -1263,7 +1263,7 @@ virtual class Text(Widget):
             _draw_text(fb, fw, fh, self.x + 4, prompt_y, &self.prompt[0], self.prompt_color)
             if self.input_len > 0:
                 _draw_text(fb, fw, fh, self.x + 4 + plen * CHAR_W, prompt_y,
-                           &self.input_buf[0], uint32(0xFFFFFF))
+                           &self.input_buf[0], self.text_color)
             cx_pos: int = self.x + 4 + (plen + self.cursor_pos) * CHAR_W
             if cx_pos < self.x + self.w - 4:
                 _fill_rect(fb, fw, fh, cx_pos, prompt_y, CHAR_W // 2, CHAR_H, self.cursor_color)