feat(ui): right rail as vertical tabs with sideways labels

Replace the right rail's collapsed launcher cards with a vertical tab
strip: one sideways tab per panel, the open panel beside it, at most one
panel open in every HUD layout. The panels' collapsed classes stay the
source of truth; the strip mirrors them and routes every change through
setPanelCollapsed, so persistence and share links are unchanged. Phones
keep the sheet shell.

Five presentations, picked with data-rail-tabs on the rail: cards-down
(default), cards-up, spine, icons and minimal.

The one-owner rule, previously Cyber-only, now applies to every desktop
layout, so the right rail's Tactical auto-collapse retry path is dead and
removed. Escape inside a panel returns focus to the panel's tab.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

scripts/format-scope.json

@@ -1117,5 +1117,8 @@
   "src/testSupport/shareViewFixtures.mjs",
   "src/ui/shareLinks.test.mjs",
   "src/ui/shareButton.test.mjs",
-  "src/share/shareLinkPath.test.mjs"
+  "src/share/shareLinkPath.test.mjs",
+  "src/ui/rightRailTabs.js",
+  "src/ui/rightRailTabs.test.mjs",
+  "src/ui/styles/right-rail-tabs.css"
 ]

scripts/package-boundaries.json

@@ -762,6 +762,7 @@
       "src/ui/radioTunerModel.js",
       "src/ui/recordingControls.js",
       "src/ui/rightPanelRail.js",
+      "src/ui/rightRailTabs.js",
       "src/ui/sceneControls.js",
       "src/ui/scenePresentation.js",
       "src/ui/actionButton.js",
@@ -2287,6 +2288,7 @@
       "src/ui/radioTunerModel.js",
       "src/ui/recordingControls.js",
       "src/ui/rightPanelRail.js",
+      "src/ui/rightRailTabs.js",
       "src/ui/sceneControls.js",
       "src/ui/scenePresentation.js",
       "src/ui/actionButton.js",
@@ -3352,6 +3354,7 @@
       "src/ui/panelRailGeometry.js",
       "src/ui/panelRails.js",
       "src/ui/rightPanelRail.js",
+      "src/ui/rightRailTabs.js",
       "src/ui/uiLifetime.js",
       "src/i18n/index.js",
       "src/i18n/locale.js",