Derive data protection from a module's declared data (hq ADR 0233)

A module's data section says what it keeps and how precious it is; the backup holder's lines,
binding stickiness, retirement on unassign and D13's conditions follow from it, so issue 273's
empty replacement is said and an unassigned module's data is remembered, not forgotten.

cmd/mesh-controller/doctor.go

@@ -102,6 +102,14 @@ var probeRegistry = []probe{
 	{ID: probeBindingsID, Asserts: "every consumer of a provision that keeps its data is bound where it was last " +
 		"sent, or moves by a pin", From: "issue 273, ADR 0232", Kind: kindBindingMoved,
 		Raises: []string{kindBindingKept, kindBindingMoving}, Phase: 2, run: probeBindings},
+	{ID: probeDataID, Asserts: "every item of data a machine declares is measured, is there, holds what it held, is " +
+		"written where it should be, is backed up within its bound or sits on healthy redundant storage, and is no " +
+		"empty replacement of a copy kept elsewhere; what a machine no longer declares that is irreplaceable or " +
+		"valuable is retired, not forgotten", From: "issue 273, ADR 0233",
+		Kind: kindDataShrank, Raises: []string{kindEmptyReplacement, kindDataHeldTwice, kindDataQuiet, kindBackupStale,
+			kindDataUnmeasured, kindDataMissing, kindArrayDegraded, kindProtectionMissing, kindCleanupWaiting},
+		Phase: 2, run: probeData,
+		Asks: []broker.SeatVerb{{Seat: "node-backup", Verb: "backed-up"}}},
 	{ID: "DW", Asserts: "the watchdogs of the signals table ran within three of their intervals",
 		From: "ADR 0227 rule 6: the watchers are watched", Kind: "watchdogs-silent", Phase: 1, run: probeWatchdogs},
 }