feat(ui): F8-09 — turn report sticky icon-popup section menu (#52)

- Replace the 14 rem sticky sidebar (and its mobile <select> twin)
  with a single sticky icon-popup trigger pinned to the top-right
  corner of the report column. Trigger shows `≡` followed by the
  currently active section title (CSS-clamped with text-overflow:
  ellipsis so long RU titles cannot bloat the button). Click opens
  an anchored popover on desktop and a fixed bottom-sheet on
  <768.98 px (mirrors lib/active-view/map-toggles.svelte).
- Each menuitem closes the popover and scrolls the matching
  `<section id="report-<slug>">` into view. The scroll is deferred
  one animation frame so the surface unmount + restoreFocus's
  focus restoration on the (sticky) trigger commit first; otherwise
  the focus call could cancel the just-started smooth/instant
  scroll under desktop Chromium and WebKit.
- Drop the in-report "Back to map" button — the same affordance
  lives in the app-shell view menu (tests/e2e/game-shell.spec.ts
  covers it).
- Tighten the report grid to a single flex column so the section
  body now occupies the full container width.
- i18n: remove game.report.back_to_map and
  game.report.toc.mobile_label; add game.report.toc.open and
  game.report.toc.close (mirrors game.map.toggles.open/close).
- Tests: Vitest report-toc.test.ts rewritten for the new icon-popup
  contract; Playwright report-sections.spec.ts switches the anchor
  loop to trigger → menuitem and adds a mobile bottom-sheet
  assertion; game-shell-stubs.test.ts no longer asserts the
  back-to-map button on the report orchestrator.
- Docs: ui/docs/report-view.md (TOC + i18n + test seams) and
  docs/FUNCTIONAL{,_ru}.md §6.4 updated. The stale SvelteKit
  Snapshot reference (the route file was removed by the single-URL
  app-shell) is dropped at the same time.

Refs: #52 (#43 umbrella).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ui/frontend/src/lib/i18n/locales/ru.ts

@@ -604,9 +604,9 @@ const ru: Record<keyof typeof en, string> = {
 	"game.inspector.planet.ship_groups.race.unknown": "неизвестно",
 
 	"game.report.loading": "загрузка отчёта…",
-	"game.report.back_to_map": "назад к карте",
 	"game.report.toc.title": "разделы",
-	"game.report.toc.mobile_label": "перейти к разделу",
+	"game.report.toc.open": "показать список разделов",
+	"game.report.toc.close": "скрыть список разделов",
 	"game.report.section.galaxy_summary.title": "общие сведения о галактике",
 	"game.report.section.galaxy_summary.field.turn": "ход",
 	"game.report.section.galaxy_summary.field.size": "размер карты",