shell_token now picks the quoting style per platform: single quotes on
POSIX (sh expands nothing inside them, so backslash runs, $VAR, and
backticks reach the compiler exactly as lexed, matching SCons's
no-shell spawn) and the CreateProcess argv rule on Windows. A test
round-trips every case through a real /bin/sh.
The ninja and ccache runnability probes collapse into one
tool_version_runs helper in framework_helpers. The registry names a
non-dict top-level payload like the inner guards, and the expect layout
check also runs on marker hits so a marked install that later lost
files fails by name. The ESP-IDF ccache gate defers to
resolve_ccache_path so ESPHOME_CCACHE_ENABLE=0 disables ccache there
too, with IDF_CCACHE_ENABLE still taking precedence.