release: 0.6.0: Delivery detail page, DNS badge, machine metrics, wide layout

A page per delivery (`/deliveries/{id}`), reached from the *Details* link on
Added:
  - A page per delivery (`/deliveries/{id}`), reached from the *Details* link on
  - A **DNS** badge in the domain list, one per row, carrying the same
  - Machine metrics on the status page: a **Machine** card reporting the
  - An index of the current page's own sections in the navigation column, for the
Changed:
  - Every panel page is laid out in one column of the same width, so moving
  - The mark's small-size variant — the tab icon and the `SP` initials it
  - The stamp's `SELF-HOSTED SMTP RELAY` line is set at 11.5/0.15 instead of
  - The delivery log lists what identifies a message and nothing else: time,
  - Subjects are decoded for display as well as on the way in, so the rows the
  … (4 more in CHANGELOG)

Full detail: CHANGELOG.md (0.6.0).

internal/web/web.go

@@ -84,6 +84,11 @@ type Server struct {
 	sessions *sessionStore
 	setup    *setupManager
 	dns      *dnscheck.Checker
+	// machine reads the host's CPU, memory and network counters for the
+	// status page. It has to be one shared sampler for the whole server:
+	// CPU and throughput are differences between successive readings, so a
+	// per-request sampler would never have a previous one to subtract.
+	machine health.MachineSampler
 
 	loginLimiter *rateLimiter
 	setupLimiter *rateLimiter
@@ -193,6 +198,7 @@ func (s *Server) Handler() http.Handler {
 	// and /body endpoints return HTML, not JSON).
 	authed.HandleFunc("GET /deliveries", s.handleDeliveries)
 	authed.HandleFunc("GET /deliveries/rows", s.handleDeliveriesRows)
+	authed.HandleFunc("GET /deliveries/{id}", s.handleDelivery)
 	authed.HandleFunc("GET /mail-queue", s.handleMailQueue)
 	authed.HandleFunc("GET /mail-queue/body", s.handleMailQueueBody)
 	authed.HandleFunc("GET /system-log", s.handleSystemLog)