Checklist z27ag-captures v2: jack-stands section (23-26), conditions from the first run

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

docs/impl/plans/Z27AG-CAPTURES.md

@@ -42,17 +42,26 @@ They are data: [`checklists/z27ag-captures.json`](../../../checklists/z27ag-capt
 bundled into the app as an exact copy (app-flutter `tool/sync-contracts.sh`;
 crosscheck fails if the copy drifts). Edit them there; bump `version` when steps
 change meaning, since every recording names the version it was made with. Before
-starting: PEAK on the OBD port, Orin up, tablet connected; engine off, doors shut.
+starting: PEAK on the OBD port, Orin up, tablet connected, and `can_pcan` UP (the
+recorder refuses marks with "no session" otherwise); engine off, doors shut.
 
-- **Parked, ignition on, engine off** (1–13): baseline, pedals, steering, gears
+- **Parked, ignition on, engine off, handbrake on** (1–13): baseline, pedals, steering, gears
   (reverse likely shows as the reverse light: the diesel forfour carries it in
   `423` byte 1 bit 3; no other gearbox signal expected), handbrake, indicators,
   lights, doors, wipers, A/C, belt.
-- **Engine running, parked** (14–18): start and idle, held revs (OBD rpm is the
-  reference), blips, A/C load, radiator fan.
+- **Engine running, parked** (14–18): start and idle, held revs in neutral (no OBD
+  on this car's CAN: the revs are approximate, read off the tacho), blips, A/C load, radiator fan.
 - **Driving** (19–22): steady speeds, stops, corners, each gear. A passenger presses,
-  or skip the marks: OBD and GNSS speed are recorded continuously, and gear comes
-  from rpm ÷ speed.
+  or skip the marks: GNSS speed is recorded continuously, and gear comes from
+  rpm ÷ speed.
+- **On jack stands** (23–26, since v2): front wheels up, rears chocked, handbrake
+  off. Unpowered steering; speedometer readings held in 2nd and 3rd (fronts turn,
+  rears stay still, which tells the wheels apart); braking from speed with vacuum
+  assist; reverse. Stands replace the driving speeds where a drive is not practical.
+
+Version 2 (2026-10-13) adds the stands section and writes down the conditions the
+first run showed matter: engine off and handbrake on for 1–13, foot brake held for
+the handbrake step, neutral with the clutch up for the revs.
 
 The parked steps can be split over several sessions; the drive is the important part.