Fix esptool detection and baud rate issues in Windows batch scripts (#7856)

- Fix esptool detection to use 'version' subcommand instead of no arguments
- Fix device-update.bat to use 115200 bps for flashing, 1200 bps only for reset
- Add missing closing quotes in debug messages

Replace magic numbers with named constants for better maintainability

- Add RESET_BAUD=1200 constant for reset baud rate
- Add UPDATE_OFFSET=0x10000 constant for update flash offset
- Use constants instead of hardcoded values throughout script

Extract magic numbers to constants in shell scripts for consistency

- Add FLASH_BAUD, RESET_BAUD, UPDATE_OFFSET constants to device-update.sh
- Add RESET_BAUD, FIRMWARE_OFFSET constants to device-install.sh
- Replace hardcoded values with named constants throughout
- Maintain consistency with batch script improvements

Fix Python path quoting and remove unreachable code

- Quote Python interpreter paths to handle spaces in paths like 'C:\Program Files\Python\python.exe'
- Remove unreachable GOTO statements after EXIT /B commands
- Improve robustness when custom Python interpreters are specified

Fix esptool detection for pipx installations

- Change from checking ERRORLEVEL GEQ 2 to EQU 9009
- Pipx-installed esptool returns exit code 2 when showing help (normal)
- Only treat Windows 'command not found' error (9009) as truly not found
- Add debug output to show actual exit codes for troubleshooting

bin/device-install.bat

@@ -119,11 +119,10 @@ IF NOT "__%PYTHON%__"=="____" (
 
 CALL :LOG_MESSAGE DEBUG "Checking esptool command !ESPTOOL_CMD!..."
 !ESPTOOL_CMD! >nul 2>&1
-IF %ERRORLEVEL% GEQ 2 (
-    @REM esptool exits with code 1 if help is displayed.
+IF %ERRORLEVEL% EQU 9009 (
+    @REM 9009 = command not found on Windows
     CALL :LOG_MESSAGE ERROR "esptool not found: !ESPTOOL_CMD!"
     EXIT /B 1
-    GOTO eof
 )
 IF %DEBUG% EQU 1 (
     CALL :LOG_MESSAGE DEBUG "Skipping ESPTOOL_CMD steps."