R-528 (09 decision 157): after a Docker engine step the wrapper proves the engine reports a memory kill

felhom-os-apply: a docker-layer apply runs oom_check() after health_after and reports
"oom_check": {result pass|fail|error, oom_killed, oom_event, exit_code, image, detail}.
One throwaway container (the controller's image, --pull never, --network none, 64m cap,
label felhom.oomcheck=1) runs dd bs=200M; pass only with OOMKilled=true AND the oom event
(read after a 2 s settle, --until = guest epoch + 1: measured on demo-hp, an --until taken
right after the run missed the event). docker rm -f always runs in a finally; every call
is bounded (<= 90 s). It never changes the step's outcome or health. New wrapper-only mode
"oom-check" (docker layer) runs the check alone; check_guest etc. still apply.

Agent: WrapperReport/Report gain OOMCheck (json:"oom_check"), copied unchanged in runLayer
and in the kept-copy path.

Tests: 9 wrapper tests + 2 Go tests, each red-proofed (audits/readback-2026-10-07/F/red-*.txt).
Also: test_felhom_os_apply.py's `if __name__` sat mid-file, so 11 tests (UnsentReport,
SaveReportOnDisk, AgentDiesMidPass, CrashLeftTheJournal) never ran as a script or from
TestWrapperSuite; moved to the end (they pass).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

internal/osupdate/leg.go

@@ -106,6 +106,9 @@ type WrapperReport struct {
 	LiveRestore         json.RawMessage `json:"live_restore"`
 	Facts               json.RawMessage `json:"facts"`
 	Bundle              json.RawMessage `json:"bundle"` // the config bundle's result (R-840, mode "bundle")
+	// OOMCheck (R-528, `09` decision 157): the docker layer's memory-kill check, {result, oom_killed, oom_event,
+	// exit_code, image, detail}. Carried to the hub UNCHANGED; the agent never reads it.
+	OOMCheck json.RawMessage `json:"oom_check"`
 	// R-868 (v0.144.0): the agent's ids, echoed from the plan, so a report kept on disk can be sent without the
 	// agent process that started the pass. ReleaseID / VMID were always in the report.
 	RunID     string `json:"run_id"`
@@ -143,6 +146,9 @@ type Report struct {
 	DockerEngine        string          `json:"docker_engine,omitempty"` // docker layer: the engine after the step
 	Authority           string          `json:"authority,omitempty"`     // docker layer: ring0 | signed
 	Undo                bool            `json:"undo,omitempty"`          // docker layer: a signed undo (downgrade)
+	// OOMCheck: docker layer — the wrapper's oom_check object, byte-for-byte (R-528; the hub decides approval on it).
+	// Pinned by TestDocker_OOMCheckReachesTheHubUnchanged and TestR868_KeptCopyCarriesTheOOMCheck.
+	OOMCheck json.RawMessage `json:"oom_check,omitempty"`
 
 	unsent string // R-868: the wrapper's kept copy of this pass's report — deleted once the hub has it
 }
@@ -630,6 +636,7 @@ func (l *Leg) runLayer(ctx context.Context, runID, layer string, vmid int, trigg
 	}
 	rep.Upgraded, rep.PassSeconds = wr.Upgraded, wr.PassSeconds
 	rep.DockerEngine, rep.Authority, rep.Undo = wr.DockerEngine, wr.Authority, wr.Undo
+	rep.OOMCheck = rawOrNil(wr.OOMCheck)
 	if rep.Outcome == "" {
 		switch {
 		case rep.Mode == "inventory" && !blk.Enabled:
@@ -707,6 +714,14 @@ func (l *Leg) runLayer(ctx context.Context, runID, layer string, vmid int, trigg
 	return l.finish(ctx, lg, rep)
 }
 
+// rawOrNil: a wrapper field that is absent or JSON null stays out of the hub report (omitempty).
+func rawOrNil(m json.RawMessage) json.RawMessage {
+	if len(m) == 0 || string(m) == "null" {
+		return nil
+	}
+	return m
+}
+
 func onlyDocker(in []Package) []Package {
 	var out []Package
 	for _, p := range in {