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.

src/i18n/locales/ja.json

@@ -2649,7 +2649,6 @@
   "RECENT IMAGERY": "最近の衛星画像",
   "Imagery days in the box": "範囲内の画像のある日",
   "CONTEXT": "コンテキスト",
-  "Expand panel": "パネルを展開",
   "Context mode": "コンテキストモード",
   "CONTACTS": "コンタクト",
   "Cycles the nearest contacts of whatever type you select — planes, vessels, installations. Satellites track independently.": "選択した種類（航空機、船舶、施設）の最寄りのコンタクトを順に切り替えます。衛星は独立して追跡されます。",