CAT-P2: the overview page: a handler that answers GET only, on a port for this machine only, through a required route

The module's bundle (the one process with the bus) serves the page on the port its manifest declares under listens, from: machine,
and requires a route that reaches it. No form, no script, no verb behind it; any method but GET is 405. A source that does not
answer is said on the page, never shown as an empty list.

Issue 1968.

Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig

modules/mesh-knowledge/module.json

@@ -4,6 +4,7 @@
   "slug": "knowledge",
   "requires": [
     "postgres-database",
+    "route",
     {
       "name": "records", "storage": "ledger", "template": "ledger", "options": {"max-mib": 1024},
       "types": [
@@ -82,11 +83,25 @@
   "contributes": {
     "postgres-database": {
       "name": "knowledge"
+    },
+    "route": {
+      "label": "knowledge",
+      "endpoint": "overview"
     }
   },
   "binds": {
-    "postgres-database": "${dir:state}/database.json"
+    "postgres-database": "${dir:state}/database.json",
+    "route": "${dir:state}/route.json"
   },
+  "listens": [
+    {
+      "name": "overview",
+      "port": 8480,
+      "protocol": "tcp",
+      "from": "machine",
+      "why": "the overview page, read-only: only a process on this machine reaches it, and the operator through the route proxy (novox/hq ADR 0616 §4)"
+    }
+  ],
   "secrets": {
     "postgres-database": "${dir:state}/database.secret"
   },