Builder: write each build's start and end to its own log on the bus, and ask the seat artifact-store's held and hear its artifacts-gone, the controller's only until the lease write, so build history and the store's sweep leave the controller (issue 1955, ADR 0571 §1, §2)

Pins mesh-sdk f9a496d.

modules/mesh-delivery-builder/module.json

@@ -13,11 +13,13 @@
     "build.asked-again"
   ],
   "consumes": [
+    "artifact-store.artifacts-gone",
     "mesh-build-go.toolchain.reported",
     "mesh-build-node.toolchain.reported",
     "mesh-controller.artifacts-gone"
   ],
   "invokes": [
+    "seat:artifact-store.held",
     "seat:mesh-controller.held"
   ],
   "state": [
@@ -27,6 +29,16 @@
     { "name": "queues", "history": 1 },
     { "name": "reasks", "history": 1 }
   ],
+  "streams": [
+    {
+      "name": "log",
+      "events": [
+        "build.started",
+        "build.ended"
+      ],
+      "max-age-days": 30
+    }
+  ],
   "reads": [
     "mesh-build-go.steps",
     "mesh-build-go.toolchains",
@@ -44,7 +56,6 @@
     "node-build-image",
     "node-build-node"
   ],
-
   "own-secrets": {
     "broker": "${dir:state}/broker"
   },