docs(ui): sync docs to the app-shell; fix stale nav comments

Rewrite ui/docs (navigation, order-composer, auth-flow, pwa-strategy,
game-state + secondary topic docs) and ui/README for the single-URL
app-shell (in-memory screens/views, Back→lobby via shallow routing,
sessionStorage restore + validation, return-to-lobby). ui/PLAN.md gets a
Phase-10 supersede note (implemented; standalone-compatible). Fix stale
code comments (session-store auth gate, report-sections spec contract).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/docs/report-view.md

@@ -107,36 +107,23 @@ visible area so that scrolling down advances the highlight
 naturally. The observer is created on mount and torn down on
 unmount.
 
-The in-game shell layout (`routes/games/[id]/+layout.svelte`)
+The in-game shell (`lib/game/game-shell.svelte`)
 expands `<main class="active-view-host">` to fit content rather
 than constraining it, so the document body is the actual scroll
 container — not the host. The IntersectionObserver root is `null`
 to match.
 
-## Scroll save / restore
+## Scroll position
 
-`routes/games/[id]/report/+page.svelte` exports a SvelteKit
-`Snapshot<{ scrollY: number }>`:
-
-- `capture()` reads `window.scrollY` when SvelteKit's
-  `beforeNavigate` cycle runs.
-- `restore(value)` schedules a short
-  `requestAnimationFrame` poll that waits for
-  `document.documentElement.scrollHeight` to grow tall enough to
-  honour the saved offset, then calls `window.scrollTo(0, value)`.
-  The poll caps at ~60 frames (≈ 1 second) so a never-tall-enough
-  body never pins a frame loop.
-
-The capture / restore pair is keyed by route, so:
-- Forward navigation from `/report` to `/map` lands `/map` at
-  scrollY 0 (no snapshot for `/map` to restore from).
-- History-back from `/map` to `/report` restores the previously
-  captured scrollY — the user returns to the same section.
-
-The Snapshot API does not capture the active sidebar slug; the
-IntersectionObserver re-derives it from the restored scroll
-position on the next animation frame, which keeps the TOC
-highlight consistent without a second source of truth.
+The report is the `report` active view; switching to another view is
+an in-memory `activeView` state change, not a navigation, and the
+report component is remounted when the user returns to it. The
+single-URL app-shell therefore does not carry SvelteKit's route-keyed
+`Snapshot` scroll save/restore — that mechanism was tied to the old
+`/games/:id/report` route and was removed with it. A re-entered report
+opens at the top; the IntersectionObserver re-derives the active TOC
+slug from the scroll position on the next animation frame, so the
+highlight stays consistent without a separate source of truth.
 
 ## i18n namespace
 
@@ -169,10 +156,13 @@ couple them silently.
   / IntersectionObserver are out of scope.
 - **Playwright** — `tests/e2e/report-sections.spec.ts` exercises
   the full integration: every TOC anchor lands its section in
-  view, the snapshot mechanism preserves `window.scrollY` on
-  history navigation, the back-to-map button reaches `/map`, the
-  mobile `<select>` scrolls to the chosen section on a narrow
-  viewport.
+  view, the back-to-map button switches to the map view
+  (`activeView.select("map")`), and the mobile `<select>` scrolls
+  to the chosen section on a narrow viewport. The spec drives the
+  app-shell through `window.__galaxyNav` (the dev-only nav surface)
+  instead of `page.goto` per-view URLs. The old "scroll position
+  survives a `/map` round-trip via SvelteKit `Snapshot`" case was
+  dropped — see the [scroll position](#scroll-position) note.
 
 Test IDs follow the pattern `report-section-<slug>` for section
 roots, `report-toc-<slug>` for TOC anchors, and per-section row