README: two explicit install paths; Windows launchers pass --db and quote paths

- the Install section now leads with the release artifacts (the wheel via
  pipx/pip, the direct release URL, `gh release download` for the
  version-agnostic case, and the source archive) and keeps the git clone as
  the development path.  It finally names the launchers (./start.sh,
  start.bat): a clone needs no install, but the README never said how to start
  it while the Running section only showed the console script that an install
  provides.
- Windows: the USB section now says the .bat launchers mirror the shell ones
  and call the `python` command (Python 3 must be on PATH); the Install section
  carries the same note.
- start.bat: --db/DB was parsed and then never passed to the server; it is
  passed now, and --gsmtap-port is sent only for gsmtap capture (as start.sh
  already did).  Both .bat files passed values unquoted and stripped the
  quotes of pass-through options, so paths with spaces broke
  (--db "C:\My Data\...", --web-dir, --pcap, --output); values are quoted now
  and pass-through keeps the original quoting (argument assembly through
  delayed expansion).
- the launcher usage comments include the `disabled` capture mode.
- verified the argument assembly with Wine cmd.exe and an echo harness: the
  quoted paths survive, --db arrives, --gsmtap-port appears only for gsmtap;
  547 Python + 80 Node tests.

sniff-start.bat

@@ -59,7 +59,7 @@ if "%~1"=="--inactivity-timeout" (
     shift
     goto :parse_args
 )
-set "EXTRA_ARGS=!EXTRA_ARGS! %~1"
+set "EXTRA_ARGS=!EXTRA_ARGS! %1"
 shift
 goto :parse_args
 
@@ -67,11 +67,11 @@ goto :parse_args
 echo Starting simtrace2-pysniff...
 
 set "ARGS="
-if not "%GSMTAP%"=="" set "ARGS=!ARGS! --gsmtap %GSMTAP%"
-if not "%PCAP%"=="" set "ARGS=!ARGS! --pcap %PCAP%"
-if not "%OUTPUT%"=="" set "ARGS=!ARGS! --output %OUTPUT%"
-if not "%FORMAT%"=="" set "ARGS=!ARGS! --format %FORMAT%"
-if not "%INACTIVITY_TIMEOUT%"=="0" set "ARGS=!ARGS! --inactivity-timeout %INACTIVITY_TIMEOUT%"
+if not "%GSMTAP%"=="" set "ARGS=!ARGS! --gsmtap "%GSMTAP%""
+if not "%PCAP%"=="" set "ARGS=!ARGS! --pcap "%PCAP%""
+if not "%OUTPUT%"=="" set "ARGS=!ARGS! --output "%OUTPUT%""
+if not "%FORMAT%"=="" set "ARGS=!ARGS! --format "%FORMAT%""
+if not "%INACTIVITY_TIMEOUT%"=="0" set "ARGS=!ARGS! --inactivity-timeout "%INACTIVITY_TIMEOUT%""
 
 set "PYTHONPATH=%~dp0"
-python -m simtrace2_pysniff %ARGS% %EXTRA_ARGS%
+python -m simtrace2_pysniff !ARGS! !EXTRA_ARGS!