feat(m15): nvidia-smi snapshot + display logs + inventory in reports — 0.32.0

Expand diagnostic/report collection (all stored per-diagnostic, in the Report zip;
logs also fed to the AI on "Explain"):
- syslogs: nvidia-smi -q snapshot (driver/throttle/clocks/power/temps/PCIe/ECC/
  retired pages) + display-server log auto-detected — Xorg.0.log on X11, or the
  compositor user-journal slice (gnome-shell/kwin/sway/gamescope) on Wayland.
- diagstore: include the full M5 inventory (inventory.txt + .json) — invaluable
  for larger/shared debugging. inventory.collect() degrades gracefully (no root
  prompt). Best-effort throughout.
- Tests for nvidia/display + inventory in store; docs (M15/SPEC).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_diagstore.py

@@ -47,11 +47,15 @@ class StoreTests(unittest.TestCase):
         with mock.patch.object(diagstore, "enabled", return_value=True), \
              mock.patch("rigdoctor.render.render_summary", return_value="SUMMARY-TEXT"), \
              mock.patch("rigdoctor.core.gamelogs.collect", return_value="LOG-TEXT"), \
+             mock.patch("rigdoctor.core.syslogs.collect", return_value="SYS-LOG"), \
+             mock.patch("rigdoctor.core.inventory.collect", return_value=[]), \
              mock.patch.object(diagstore.config, "DIAGNOSTICS_DIR", self.tmp / "diagnostics"):
             directory = diagstore.store(FakeResult())
         self.assertTrue((directory / "result.json").exists())
         self.assertTrue((directory / "report.txt").exists())
         self.assertEqual((directory / "gamelogs.txt").read_text(), "LOG-TEXT")
+        self.assertEqual((directory / "syslogs.txt").read_text(), "SYS-LOG")
+        self.assertTrue((directory / "inventory.txt").exists())  # inventory included for debugging
         data = json.loads((directory / "result.json").read_text())
         self.assertEqual(data["game"], "Path of Exile 2")
         self.assertEqual(len(data["findings"]), 1)