Give route-proxy its state on the bus and three tools, so a site's route, certificate and last answer are read from the mesh instead of with curl (issue 774)

The web front kept nothing on the bus: whether grafana or drive was routed, where to, with which
certificate, and what it last answered could only be learned with curl or the container's log.

The proxy now keeps `routes` and `unrouted` (announced readable, keyed <node>.<name>), written on
change by one writer: route set changes, certificates stored by autocert's cache or failing at a
handshake, upstream answers that differ from the last written (or are a minute old), and names
refused in a request or a handshake. The provider helper's bundle serves route_proxy_routes,
route_proxy_route and route_proxy_unrouted from those states.

Quick: log the routes at start and grep the journal. Thorough: the state on the bus and the tools
that read it, mesh-wide, in one call. Chose thorough: the operator's question is mesh-wide and
recurs, and the log says nothing about certificates or answers.

Tests: two table tests added (the ledger, the tools), both failing without the change; four
authority tests and four skipped-route tests merged into two, so the module has four fewer.

modules/route-proxy/README.md

@@ -90,3 +90,17 @@ A small Go program beside the proxy (`cmd/route-provider`) runs the SDK's provid
 and the offer says `"answered-by": "helper"`: a handed consumer (gitea's origins file) is filled by its machine's client
 from this module's entry, which carries the public names the controller composed for it. The module is **not** marked
 moved: its own files, `acme.env` and the broker secret, are composed as before, and the proxy itself is unchanged.
+
+## What it says on the bus, and its tools (issue 774)
+
+The proxy keeps two states, announced readable (`conn.Keeps`, novox/hq ADR 0495), each keyed `<node>.<name>`:
+
+| state | one key per | holds | written when |
+|---|---|---|---|
+| `routes` | served name | the rules it is served by (path, module, node, target, refusal, redirect, authentication); its certificate (authority, issuer, not-after, last renewal, outcome, or why it failed); the last upstream answer (status, time, error, path) | a route arrives, changes or leaves; an authority stores a certificate; a handshake fails to find one or hands out one not yet recorded; an upstream answer differs from the last one written, or the same one is a minute old |
+| `unrouted` | name answered "no route for", in a request or a TLS handshake | when it was last asked, by whom, how often since the start, whether it is an internal-only name asked from outside | first asked, then at most once a minute; deleted when the name is served; kept a week |
+
+Nothing is written on a timer. The provider helper's binary serves the module's tools from those states, one call each:
+`route_proxy_routes` (every served name with its target, certificate expiry and last answer), `route_proxy_route`
+(one name in full, or that it is not served and when it was last asked for) and `route_proxy_unrouted` (the names
+refused, newest first).