The main timeline is the only time control; the Weather panel shows its frame time

The Weather panel kept a second time transport of its own: a slider, step
buttons, Latest and Play, backed by a replay in the weather clock that
stepped the observed frames every two seconds and went round from the last
to the first. The weather clock also attached itself to the world clock as
a driver, so the timeline's Play became that replay whenever weather was on.

The panel now shows the frame time only: the newest frame and its age while
live, the timeline time alone at a past time. The weather clock no longer
has setTarget, step, latest, play, pause or togglePlay, its state no longer
has playing, and it no longer drives the world clock. It still follows the
world time, registers each product's frames as marks the timeline's arrow
keys step to, holds its products, and gates the world's continuous play at
each next frame until it loads. weatherClock.world names the world clock it
follows.

A weather row's play, latest and step params move the world clock as the
timeline does: play toggles continuous play (from the start of the covered
time when live), latest goes live, and step goes to the previous or next
mark. The rail timeline component, which only the panel used, is removed,
along with its unused messages in every locale.

docs/CODE-BOUNDARIES.md

@@ -293,9 +293,9 @@ the user's later collapse choice, including body remounts. Mark the body
 `max-height` and puts the scroll offset back afterwards. Panel bodies only
 scroll on an open-card change, with one write, never on a refresh.
 
-Compose `createRailCards({ container, document, onParams, onOpen })` and
-`createRailTimeline({ container, document, onCommit, onPreview, onStep,
-onLatest, onPlay })`. Cards reconcile `{ id, title, badge, open, compact,
+Compose `createRailCards({ container, document, onParams, onOpen })`. Rails
+have no time controls of their own; the world timeline moves time. Cards
+reconcile `{ id, title, badge, open, compact,
 compactStatus, blocks }` in place. Their full-width native button headers expose
 `aria-expanded` and `aria-controls`; articles expose `data-open`. The feature
 adapter owns accordion state. Generic cards do not select data or enable layers.
@@ -330,10 +330,9 @@ consumers. They expose `summary.settings`, `summary.actions` and optional
 subscriptions still refresh the cards. Cards own configuration and readings.
 
 Weather orders cyclones, wind, then a bordered Observed history group containing
-the timeline and active radar, satellite and lightning cards. The group heading
-and scope name its active products. The timeline stays visible whenever any
-observed product is enabled; fewer than two ticks disables transport. Pass
-`heading: false` to the timeline when the containing group owns the heading.
+the frame time and active radar, satellite and lightning cards. The group
+heading and scope name its active products. The frame time shows whenever any
+observed product is enabled and has a frame; the world timeline moves time.
 Exactly one active card is open. Header clicks and newly enabled ids choose it
 (the last new entry wins a batch); refreshes and clock ticks retain it. First
 appearance uses cyclones with storms, otherwise the first card. Disabling the
@@ -341,7 +340,7 @@ open layer falls back to the first remaining card. A WeakMap per document keeps
 explicit choices through body remounts without adding share state. Card opening,
 storm selection and layer enabling remain independent.
 
-Optional card/badge/slider class names provide feature styling. Card titles use
+Optional card/badge class names provide feature styling. Card titles use
 `.data-name` typography; meta/time/badges use `.data-toggle-meta` typography;
 setting/result labels use `.panel-title`; chips retain `.data-toggle-chip`.
 Reserve one status line, even without a legend. Use app tokens. Wind's footer