feat(panels): build the rail panels on one UiPanel

The Data, Authoring, Weather, Recent Imagery, Context, CCTV, Street Level
and Radio panels each wrote the same frame by hand. They are now one kit
component, UiPanel, with a title, badge/actions/default slots and
v-model:collapsed, drawing Core's panel markup and classes beside the kit's;
props cover the differences (sideways, glow, scroll, railScroller, tag,
toggleWords). RailPanel binds it to the panel chrome store: v-panel-state
writes its state classes at once, and its button's clicks reach PanelChrome.
UiPanelToggle is the collapse button UiPanel and PanelCollapseButton share.

UiPanel's collapsed drives the button and ui-panel--collapsed
only; the owner hides the body by writing the root's collapsed class, since
the rails measure a panel in the task that opens it. PanelCollapseButton
takes startCollapsed instead of initial and initialTitle, so a button shows
its state's glyph and words before startup presents the panel. Titles render
through t() instead of data-i18n, and the unused "Expand panel" string is
pruned. v-panel-state redraws the presented state after a re-render, in
case a root's class binding ever changes.

CHANGELOG.md

@@ -8,6 +8,14 @@
   the bottom tab bar. The rail is the first view built with Vue and Pinia,
   which now ship with the app; see docs/VUE-MIGRATION.md (samehkhamis).
 
+- The Data, Authoring, Weather, Recent Imagery, Context, CCTV, Street Level
+  and Radio panels are one component, `UiPanel` (`src/ui/kit/`), with the
+  same markup plus the kit's `ui-panel` classes, their titles translated by
+  `t()` rather than `data-i18n`; `RailPanel` binds it to the panel chrome
+  store. `PanelCollapseButton` drops its `initial` and `initialTitle` props
+  and takes `startCollapsed`, so before startup presents a panel its button
+  already shows that state's glyph, words and `aria-expanded` (samehkhamis).
+
 - The page's panels, dock, cockpit and dialogs are Vue views with the same
   markup as before. Hosts that do not initialize Core's locale pass
   `localePicker: false` to `createApplicationControls` to drop the language