Fix image caption formatting - add blank lines for proper display

Added blank lines between images and captions to ensure captions appear
on a new row below images instead of on the same line.

This follows Markdown best practices where a blank line creates a new
paragraph for the caption text.

Fixed in both STORY.md and STORY.zh-CN.md for all images.

STORY.md

@@ -25,6 +25,7 @@ None of these explanations felt complete. Users were stuck choosing between mobi
 I decided to investigate—but here's the twist: **I'd build all the diagnostic tools on the uConsole itself**, while running on battery power. If I could solve the problem using the very device experiencing it, that would prove something profound about modern development workflows.
 
 ![Debugging the 4G modem issue on uConsole itself](story-assets/uconsole-debugging-4g.jpg)
+
 *Building the solution on the device experiencing the problem—true vibe coding in action*
 
 ## The Investigation: Following the Voltage
@@ -65,6 +66,7 @@ The breakthrough came from building a new visualization: **Battery Energy Output
 I ran a complete test with FEB-4000 4000mAh batteries (100% to ~2%), capturing 4,318 data points over 2 hours 48 minutes:
 
 ![Energy Output vs Voltage with 3.45V Threshold](story-assets/feb4000-energy-output-with-threshold.jpg)
+
 *The red line shows the 4G module's minimum voltage. Everything to the right is unusable for 4G connectivity.*
 
 **The shocking result:**

STORY.zh-CN.md

@@ -25,6 +25,7 @@
 我决定调查——但有个特别之处：**我将在 uConsole 本身上构建所有诊断工具**，同时使用电池供电运行。如果我能用正在经历问题的设备来解决问题，那将证明关于现代开发工作流程的一些深刻见解。
 
 ![在 uConsole 上调试 4G 调制解调器问题](story-assets/uconsole-debugging-4g.jpg)
+
 *在遇到问题的设备上构建解决方案——真正的 vibe coding 实践*
 
 ## 调查：追踪电压
@@ -65,6 +66,7 @@
 我用 FEB-4000 4000mAh 电池进行了完整测试（100% 至约 2%），在 2 小时 48 分钟内捕获了 4,318 个数据点：
 
 ![能量输出 vs 电压（带 3.45V 阈值）](story-assets/feb4000-energy-output-with-threshold.jpg)
+
 *红线显示 4G 模块的最低电压。右侧的所有内容都无法用于 4G 连接。*
 
 **令人震惊的结果：**
@@ -119,12 +121,15 @@
 **关键发现的可视化：**
 
 ![FEB-4000 电池百分比](story-assets/feb4000-battery-percentage.jpg)
+
 *完整的放电曲线从 100% 到约 2%*
 
 ![FEB-4000 电压和电流](story-assets/feb4000-voltage-current.jpg)
+
 *电压下降和电流峰值模式*
 
 ![FEB-4000 能量输出（带阈值）](story-assets/feb4000-energy-output-with-threshold.jpg)
+
 *关键图表显示 4G 可用容量 vs 不可用容量*
 
 每个会话捕获特定时间段内电池行为的完整画面。我用它来记录智能电源调节器的前后行为。