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/active-view/report.svelte

@@ -135,20 +135,11 @@ TOC and the body iterate the same data.
 
 <style>
 	.report-view {
-		display: grid;
-		grid-template-columns: 14rem 1fr;
-		gap: 1.25rem;
+		display: flex;
+		flex-direction: column;
 		padding: 1rem 1.25rem 2rem;
 		font-family: system-ui, sans-serif;
 	}
-	.report-view > :global(.report-toc) {
-		position: sticky;
-		top: 0;
-		align-self: start;
-		padding: 0.5rem 0;
-		max-height: calc(100vh - 4rem);
-		overflow-y: auto;
-	}
 	.report-body {
 		min-width: 0;
 		display: flex;
@@ -157,16 +148,7 @@ TOC and the body iterate the same data.
 	}
 	@media (max-width: 767.98px) {
 		.report-view {
-			grid-template-columns: 1fr;
 			padding: 0.75rem;
-			gap: 0.75rem;
-		}
-		.report-view > :global(.report-toc) {
-			position: sticky;
-			top: 0;
-			background: var(--color-bg);
-			padding: 0.5rem 0;
-			z-index: 5;
 		}
 	}
 </style>