feat(school_stm32): 添加基础的 STM32F103RCT6 项目结构

- 创建了项目的基本目录结构和文件
- 添加了 CMakeLists.txt 和 Makefile 构建配置
- 创建了 main.c 文件，实现了简单的 LED 闪烁和按键检测功能
- 集成了 SEGGER RTT 库
- 添加了 .gitignore 文件，排除了不必要的生成文件

libs/SEGGER_RTT/LICENSE.md

@@ -0,0 +1,36 @@
+
+                    SEGGER Microcontroller GmbH
+                       The Embedded Experts
+
+           (c) 1995 - 2021 SEGGER Microcontroller GmbH
+          www.segger.com     Support: support@segger.com
+
+        SEGGER RTT  Real Time Transfer for embedded targets
+
+
+    All rights reserved.
+
+    SEGGER strongly recommends to not make any changes
+    to or modify the source code of this software in order to stay
+    compatible with the RTT protocol and J-Link.
+
+    Redistribution and use in source and binary forms, with or
+    without modification, are permitted provided that the following
+    condition is met:
+
+    - Redistributions of source code must retain the above copyright
+     notice, this condition and the following disclaimer.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+    CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+    DISCLAIMED. IN NO EVENT SHALL SEGGER Microcontroller BE LIABLE FOR
+    ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+    OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+    OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+    USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+    DAMAGE.