VesiScan BASIC origin: Piezo + IMU firmware initial code

- nRF52840 + SoftDevice S140 BLE firmware
- Piezo ultrasound TX driver (2MHz, 8ch MUX)
- ICM42670P IMU 6-axis driver
- Echo AFE chain (ADA2200 + ADC121S051)
- BLE NUS command parser (mpa/mpc/mdc/mec/maa/msp)
- FDS flash config storage
- pc_firm parser and ADC driver included

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -1,3 +1,15 @@
+# Archives
+*.rar
+*.zip
+*.7z
+*.tar
+*.tar.gz
+*.tgz
+
+# Claude AI
+.claude/
+docs/
+
 # Compiled binaries
 *.o
 *.hex
@@ -16,22 +28,26 @@ output/
 *.swp
 *.swo
 *~
+*.uvguix.*
+JLinkLog.txt
+*.crf
+*.d
+*.htm
+*.lnp
+*.dep
+*.axf
 
 # Segger/J-Link
 *.jlink
 
 # nRF specific
-*.zip
 sdk_config.h.bak
 
 # Windows
 Thumbs.db
 desktop.ini
+.DS_Store
 
 # Temporary files
 *.tmp
 *.bak
-
-# SDK (external dependencies)
-# components/
-# external/