Report hardware and software overviews from IOKit and sysctl in system_profiler

system_profiler now answers SPHardwareDataType and SPSoftwareDataType (and
lists them in -listDataTypes). Model, serial number, platform UUID and
provisioning UDID come from IOKit's IOPlatformExpertDevice via ioreg; CPU,
cache and memory from sysctl; the OS version from sw_vers and uname. A
field the guest does not provide is left out.

#61 instead read a separate darling-smbios.conf written by a new
generator (gen-darling-smbios.py), with hardcoded fallbacks (an Intel Core
i9, macOS 14.7, SIP enabled). iokitd reads darling-platform.plist, so
system_profiler and IOKit could report different serials and models on the
same prefix, and the generator overwrote identities imported with
configure-darling-platform.py. Reading the guest's own APIs keeps a single
source of truth: configure-darling-platform.py remains the only way to set
or provision an identity, and it is still never run by install or launch.

tests/test_system_profiler.py runs the script under sh with stub guest
commands and runs in CI.

Split from #61.

Co-authored-by: DevWebeloper <[email protected]>
Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/PLATFORM_IDENTITY.md

@@ -134,3 +134,15 @@ a per-prefix lock. Repeated writes preserve identifiers and unchanged files.
 Previewing a fresh identity generates a sample; only `--write` makes it stable.
 To restore host-derived defaults after provisioning, remove both identity files
 while stopped, so a later provisioning run cannot reimport the legacy copy.
+
+## system_profiler
+
+The prefix's `/usr/sbin/system_profiler` (installed by
+`tools/install-darling-system-profiler.py`) answers `SPHardwareDataType` and
+`SPSoftwareDataType` from the running guest: model, serial number, platform UUID
+and provisioning UDID from IOKit's `IOPlatformExpertDevice` (via `ioreg`), CPU,
+cache and memory from `sysctl`, and the OS version from `sw_vers` and `uname`. It
+keeps no identity of its own, so it reports the same values as IOKit, including any
+override saved by this tool. A field the guest does not provide is left out.
+`python3 -m unittest tests.test_system_profiler` checks the output with stub
+commands.