Add CAN communication and GPIO control functionality

- Created HAL configuration file for STM32F1xx (stm32f1xx_hal_conf.h).
- Added interrupt handler definitions in stm32f1xx_it.h.
- Implemented CAN initialization and configuration in can.c.
- Configured GPIO pins for output and external interrupts in gpio.c.
- Developed main application logic in main.c for toggling an LED and sending CAN messages.
- Implemented MSP initialization and de-initialization for CAN in stm32f1xx_hal_msp.c.
- Defined interrupt service routines in stm32f1xx_it.c for CAN and EXTI interrupts.
- Added README for project-specific libraries and PlatformIO configuration.
- Created platformio.ini for project build settings.
- Added stm32pio.ini for CubeMX integration with PlatformIO.
- Included README for testing directory to guide unit testing setup.

firmware/components/can_testing/canblinker/.vscode/launch.json

@@ -0,0 +1,47 @@
+// AUTOMATICALLY GENERATED FILE. PLEASE DO NOT MODIFY IT MANUALLY
+//
+// PlatformIO Debugging Solution
+//
+// Documentation: https://docs.platformio.org/en/latest/plus/debugging.html
+// Configuration: https://docs.platformio.org/en/latest/projectconf/sections/env/options/debug/index.html
+
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "type": "platformio-debug",
+            "request": "launch",
+            "name": "PIO Debug",
+            "executable": "/home/kymkim/Projects/modular-kbd/firmware/components/CAN/CAN-B/.pio/build/bluepill_f103c8/firmware.elf",
+            "projectEnvName": "bluepill_f103c8",
+            "toolchainBinDir": "/home/kymkim/.platformio/packages/toolchain-gccarmnoneeabi/bin",
+            "internalConsoleOptions": "openOnSessionStart",
+            "svdPath": "/home/kymkim/.platformio/platforms/ststm32/misc/svd/STM32F103xx.svd",
+            "preLaunchTask": {
+                "type": "PlatformIO",
+                "task": "Pre-Debug"
+            }
+        },
+        {
+            "type": "platformio-debug",
+            "request": "launch",
+            "name": "PIO Debug (skip Pre-Debug)",
+            "executable": "/home/kymkim/Projects/modular-kbd/firmware/components/CAN/CAN-B/.pio/build/bluepill_f103c8/firmware.elf",
+            "projectEnvName": "bluepill_f103c8",
+            "toolchainBinDir": "/home/kymkim/.platformio/packages/toolchain-gccarmnoneeabi/bin",
+            "internalConsoleOptions": "openOnSessionStart",
+            "svdPath": "/home/kymkim/.platformio/platforms/ststm32/misc/svd/STM32F103xx.svd"
+        },
+        {
+            "type": "platformio-debug",
+            "request": "launch",
+            "name": "PIO Debug (without uploading)",
+            "executable": "/home/kymkim/Projects/modular-kbd/firmware/components/CAN/CAN-B/.pio/build/bluepill_f103c8/firmware.elf",
+            "projectEnvName": "bluepill_f103c8",
+            "toolchainBinDir": "/home/kymkim/.platformio/packages/toolchain-gccarmnoneeabi/bin",
+            "internalConsoleOptions": "openOnSessionStart",
+            "svdPath": "/home/kymkim/.platformio/platforms/ststm32/misc/svd/STM32F103xx.svd",
+            "loadMode": "manual"
+        }
+    ]
+}