Let a module declare a log the controller creates and never removes (ADR 0297)

The issue tracker's history lasts seven days on the events stream and its
bucket fills toward a cap with no warning (issues 501, 502). A module may
now declare `logs`; the controller creates each as a stream on the bus
(create-or-update, never deleted or recreated, reported when undeclared),
issues it to the owner's assignments in their membership, grants the
runtime exactly the append and direct-read subjects, and raises a
condition when any module's bucket or log reaches 75% of its cap, cleared
below 70%.

cmd/mesh-controller/doctor.go

@@ -136,6 +136,11 @@ var probeRegistry = []probe{
 	{ID: "D-root", Asserts: "no agent can become root without a person on a machine where the router or a channel " +
 		"proving its sender runs: not by its own account, and not through a tool that runs its command as an account " +
 		"that can", From: "ADR 0259 §8", Kind: kindRootNotFree, Phase: 2, run: probeAgentRoot},
+	// A module's bucket or log filling toward its cap (novox/hq ADR 0297 §6): said at three quarters, cleared
+	// below seven tenths, so a store at its threshold is not raised and cleared on every run.
+	{ID: probeStoreFillID, Asserts: "every module's bucket and log holds less than three quarters of its cap; one " +
+		"said filling is cleared once it holds less than seven tenths", From: "ADR 0297, issue 501",
+		Kind: kindStoreFilling, Phase: 1, run: probeStoreFill},
 	{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},
 	// The core's health definitions (novox/hq to-be 45 §8, ADR 0236): what a core component's new build is