Rewrite the README sentences that fail the prose rules or disagree with the code

A fresh read of README.md whole against the rules of issue 157, with every
statement except measured figures checked against the code on next. Four
sentences fail the prose rules, all in sections added since 742e759: the
origin change definition, the first uses of TTL and SOA record, and the
geojs request. Five disagree with the code: the geojs request carries only
the addresses the cache does not hold; after a write fails on SQLite's hard
heap limit, the prefix handler also writes its origin changes again, and
the PTR and geolocation caches write their answers again; the test rerun on
failure drops -cover; and latitude and longitude are in degrees, which
their names do not say.

Model: fable-5-1

TODO.md

@@ -57,19 +57,14 @@ File an issue for each problem the run finds.
 
 # Completed Steps
 
-- 2026-11-11: two more tests no longer fail on a busy host. The test of the home
-  page's card refresh runs on a fake clock. The geo test in which geojs never
-  answers counts each request as it is sent, not when it reaches the server
-  (closes https://git.eeqj.de/sneak/routewatch/issues/256).
-- 2026-11-10: `github.com/mattn/go-sqlite3` is at v1.14.53, so building on the
-  host no longer prints its two C compiler warnings (closes
-  https://git.eeqj.de/sneak/routewatch/issues/245).
 - 2026-11-10: `README.md` and this file are read whole against the rules of
   https://git.eeqj.de/sneak/routewatch/issues/157, and every statement except
-  measured figures and what outside services do is checked against the code on
-  `next`. Four README sentences failed the prose rules. Five disagreed with the
-  code. Each is rewritten. Status and Next Step describe the live-feed run in
-  progress (closes https://git.eeqj.de/sneak/routewatch/issues/251).
+  measured figures is checked against the code on `next`. Four README sentences
+  failed the prose rules, on origin changes, PTR lookups and geolocation, and
+  five disagreed with the code, on units, geolocation, a failed database write
+  and `script/test`. Each is rewritten. Status and Next Step describe the
+  live-feed run in progress (closes
+  https://git.eeqj.de/sneak/routewatch/issues/251).
 - 2026-11-10: the image creates the `routewatch` user as a regular user with UID
   1000, so the build no longer warns about the system UID range (closes
   https://git.eeqj.de/sneak/routewatch/issues/248).

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/google/btree v1.1.3
 	github.com/google/uuid v1.6.0
 	github.com/hashicorp/golang-lru/v2 v2.0.7
-	github.com/mattn/go-sqlite3 v1.14.53
+	github.com/mattn/go-sqlite3 v1.14.29
 	github.com/maxmind/mmdbwriter v1.2.0
 	github.com/miekg/dns v1.1.73
 	github.com/oschwald/maxminddb-golang/v2 v2.9.0

go.sum

@@ -10,8 +10,8 @@ github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
 github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
-github.com/mattn/go-sqlite3 v1.14.53 h1:mnTM0owzUMrKuLo+0w51NUiB0ir2Fo7kFXlPt/l3BGs=
-github.com/mattn/go-sqlite3 v1.14.53/go.mod h1:6JTjA44L93a0QCyJef5YvlPoKXntQPjzWv5gtm9sB6w=
+github.com/mattn/go-sqlite3 v1.14.29 h1:1O6nRLJKvsi1H2Sj0Hzdfojwt8GiGKm+LOfLaBFaouQ=
+github.com/mattn/go-sqlite3 v1.14.29/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
 github.com/maxmind/mmdbwriter v1.2.0 h1:hyvDopImmgvle3aR8AaddxXnT0iQH2KWJX3vNfkwzYM=
 github.com/maxmind/mmdbwriter v1.2.0/go.mod h1:EQmKHhk2y9DRVvyNxwCLKC5FrkXZLx4snc5OlLY5XLE=
 github.com/miekg/dns v1.1.73 h1:uhT8nJxmTrPJYClxVxTCX+CVn6qnzSiybRk72Z6DgrE=

internal/geo/locator_internal_test.go

@@ -90,12 +90,14 @@ func parseAddresses(t *testing.T, addresses ...string) []netip.Addr {
 	return addrs
 }
 
-// fakeGeoJS is a geojs server. It sends body, or status when that is set. It
-// keeps each request's address list.
+// fakeGeoJS is a geojs server. It sends body, or status when that is set, or
+// waits for the request to end when hang is true. It keeps each request's
+// address list.
 type fakeGeoJS struct {
 	server *httptest.Server
 	body   string
 	status int
+	hang   bool
 
 	mu       sync.Mutex
 	requests []string
@@ -117,6 +119,12 @@ func (f *fakeGeoJS) serve(w http.ResponseWriter, r *http.Request) {
 	f.requests = append(f.requests, r.URL.Query().Get("ip"))
 	f.mu.Unlock()
 
+	if f.hang {
+		<-r.Context().Done()
+
+		return
+	}
+
 	if f.status != 0 {
 		w.WriteHeader(f.status)
 
@@ -134,20 +142,6 @@ func (f *fakeGeoJS) requestsSeen() []string {
 	return append([]string{}, f.requests...)
 }
 
-// hangingTransport never answers: each request waits until its context ends.
-// It counts the requests as they are sent, so the count does not depend on
-// whether one reaches a server before its time limit runs out.
-type hangingTransport struct {
-	requests atomic.Int32
-}
-
-func (h *hangingTransport) RoundTrip(r *http.Request) (*http.Response, error) {
-	h.requests.Add(1)
-	<-r.Context().Done()
-
-	return nil, r.Context().Err()
-}
-
 // openCacheDB opens a new cache.db in a temporary directory.
 func openCacheDB(t *testing.T, dir string) *sql.DB {
 	t.Helper()
@@ -391,15 +385,13 @@ func TestLookupFallsBackToTheDatabase(t *testing.T) {
 
 			fake := newFakeGeoJS(t, tt.body)
 			fake.status = tt.status
+			fake.hang = tt.hang
 			dir := t.TempDir()
 			locator := newTestLocator(t, fake, openCacheDB(t, dir), dir)
-			requestCount := func() int { return len(fake.requestsSeen()) }
+			locator.timeLimit = shortTimeLimit
 
-			if tt.hang {
-				hanging := &hangingTransport{}
-				locator.client = &http.Client{Transport: hanging}
-				locator.timeLimit = shortTimeLimit
-				requestCount = func() int { return int(hanging.requests.Load()) }
+			if !tt.hang {
+				locator.timeLimit = testTimeLimit
 			}
 
 			giveDatabase(t, locator)
@@ -421,8 +413,8 @@ func TestLookupFallsBackToTheDatabase(t *testing.T) {
 			// asks geojs again.
 			lookupOne(t, locator, testAddress)
 
-			if requests := requestCount(); requests != 2 {
-				t.Errorf("%d requests, want 2", requests)
+			if requests := fake.requestsSeen(); len(requests) != 2 {
+				t.Errorf("%d requests, want 2", len(requests))
 			}
 		})
 	}

internal/server/home_internal_test.go

@@ -275,66 +275,49 @@ func TestPagesServeTheCopyOfTheCards(t *testing.T) {
 	}
 }
 
-// TestKeepHomeCardsFreshWorksThemOutEveryInterval runs keepHomeCardsFresh. It
-// works the cards out at once, again an interval after the table changes, and
-// stops when its context ends. It runs in a synctest bubble, whose clock is
-// fake, so a stall on the host cannot fail it.
+// TestKeepHomeCardsFreshWorksThemOutEveryInterval runs keepHomeCardsFresh with
+// a short interval. It works the cards out at once, again after the table
+// changes, and stops when its context ends.
 func TestKeepHomeCardsFreshWorksThemOutEveryInterval(t *testing.T) {
 	t.Parallel()
 
-	const interval = time.Minute
+	const (
+		interval = 10 * time.Millisecond
+		maxWait  = 15 * time.Second
+	)
 
 	table := emptyTable()
 	announce(table, "1.0.0.0/24", twoPrefixASN, testPeer(1), testRouteTime(0))
 
 	s := newServerWithTable(t, table)
 
-	// newestRouteOrigin returns the origin AS of the newest route on the
-	// cards, or 0 when there is none.
-	newestRouteOrigin := func() int {
-		cards := s.cards.Load()
-		if cards == nil || cards.NewestRoute == nil {
-			return 0
-		}
+	ctx, cancel := context.WithCancel(t.Context())
+	stopped := make(chan struct{})
 
-		return cards.NewestRoute.OriginASN
+	go func() {
+		s.keepHomeCardsFresh(ctx, interval)
+		close(stopped)
+	}()
+
+	newestRouteASNIs := func(asn int) bool {
+		cards := s.cards.Load()
+
+		return cards != nil && cards.NewestRoute != nil &&
+			cards.NewestRoute.OriginASN == asn
 	}
 
-	synctest.Test(t, func(t *testing.T) {
-		ctx, cancel := context.WithCancel(t.Context())
-		stopped := make(chan struct{})
+	waitUntil(t, maxWait, func() bool { return newestRouteASNIs(twoPrefixASN) })
 
-		go func() {
-			s.keepHomeCardsFresh(ctx, interval)
-			close(stopped)
-		}()
+	announce(table, "8.8.8.0/24", newestRouteASN, testPeer(2), testRouteTime(1))
+	waitUntil(t, maxWait, func() bool { return newestRouteASNIs(newestRouteASN) })
 
-		synctest.Wait()
+	cancel()
 
-		if got := newestRouteOrigin(); got != twoPrefixASN {
-			t.Fatalf("at the start, the newest route's AS is %d, want %d",
-				got, twoPrefixASN)
-		}
-
-		announce(table, "8.8.8.0/24", newestRouteASN, testPeer(2),
-			testRouteTime(1))
-		time.Sleep(interval)
-		synctest.Wait()
-
-		if got := newestRouteOrigin(); got != newestRouteASN {
-			t.Fatalf("an interval after the table changed, the newest "+
-				"route's AS is %d, want %d", got, newestRouteASN)
-		}
-
-		cancel()
-		synctest.Wait()
-
-		select {
-		case <-stopped:
-		default:
-			t.Fatal("keepHomeCardsFresh did not stop when its context ended")
-		}
-	})
+	select {
+	case <-stopped:
+	case <-time.After(maxWait):
+		t.Fatal("keepHomeCardsFresh did not stop when its context ended")
+	}
 }
 
 // TestStartedServerWorksOutTheCards starts a server and waits until its home