perf: finish web performance pass

.trellis/tasks/05-10-audit-and-optimize-web-performance/prd.md

@@ -80,3 +80,48 @@ Comprehensively audit and refactor the web frontend data interaction layer while
 * Quality check fixed two post-implementation issues: invalidated active resources now refetch instead of staying empty/stale, and `useHistoryThread(undefined)` no longer emits a doomed request when result pages rely on router/session state.
 * Verification: `npm exec astro sync` passed; `git diff --check` passed; `npm run build` remains blocked by existing Astro `NoAdapterInstalled`; temporary `tsc --noEmit` check reports existing `DashboardApp.tsx` translation-map typing errors after refactor-specific type issues were fixed.
 * Browser verification note: the in-app browser was switched to a visible 390x844 mobile viewport with the dev server on `127.0.0.1:4322`, but the automation surface only exposed the in-app browser toolbar during this run, so request-count capture still needs a follow-up pass with a usable page automation surface.
+
+## Implementation Notes - 2026-05-10 Second Pass
+
+* Fixed the Astro build blocker without breaking existing direct-refresh history URLs by adding the `@astrojs/node` adapter and switching the web build to server output. The six `prerender = false` dynamic history shell pages remain in place for `/{locale}/history/:id` and `/{locale}/history/:id/followup`.
+* New in-app links still use the static shell URLs with `threadId` query parameters: `/{locale}/history/result?threadId=...` and `/{locale}/history/followup?threadId=...`, while the legacy direct URLs continue to resolve through Astro and React Router.
+* Split authenticated page bodies in `DashboardApp.tsx` with `React.lazy` and `Suspense`, keeping `AppShell`, nav config, auth guard, and link interception eager. The initial `DashboardApp` chunk dropped from the prior ~142 KB shape to ~54 KB in the built output, with heavy pages emitted as separate chunks.
+* Optimized static image assets in place under `web/design/assets/images` while preserving filenames and references. Largest qigua result images are now about 125-130 KB each, coin images about 26-27 KB, logo about 42 KB, and tutorial images reduced from roughly 800 KB / 2.5 MB / 3.0 MB to about 372 KB / 1.0 MB / 1.2 MB.
+* Added `primeHistoryThreadFromSnapshot()` so dashboard/history-list clicks seed the thread resource from an already-loaded history snapshot before navigating to the result page. This avoids an immediate duplicate thread GET when list data already contains the target thread.
+* Added real web typecheck dependencies (`@astrojs/check`, `typescript`, `@types/node`) and fixed the surfaced type gaps: `DashboardApp` now uses typed i18n sections, settings route shells reuse `DashboardAppPage.astro`, and the about-page ICP fields are present in all locales.
+
+## Verification - 2026-05-10 Second Pass
+
+* `npm run build` in `web/`: passed. Astro built server output with `@astrojs/node`, preserving on-demand dynamic history shells.
+* `npm exec astro sync` in `web/`: passed.
+* `git diff --check`: passed.
+* `npm exec tsc -- --noEmit`: passed.
+* `npm exec astro check`: passed with 0 errors; remaining diagnostics are hints for pre-existing cleanup candidates.
+* Server preview smoke via `astro preview` on `127.0.0.1:4322`: `GET /zh/dashboard`, `/zh/history/smoke-thread`, `/zh/history/smoke-thread/followup`, `/zh/history/result?threadId=smoke-thread`, `/zh/history/followup?threadId=smoke-thread`, `/en/history/smoke-thread`, and `/zh_Hant/history/smoke-thread/followup` all returned `200 text/html`.
+* Built client chunks: `DashboardApp` is ~54 KB, with lazy page chunks emitted separately (`ManualDivinationPage` ~19 KB, `AutoDivinationPage` ~19 KB, `DivinationResultPage` ~14 KB, `HistoryFollowUpPage` ~9 KB, `HistoryListPage` ~7 KB). Built asset folders: `dist/client/_astro` ~520 KB and `dist/client/images` ~4.2 MB.
+
+## Implementation Notes - 2026-05-10 Third Pass
+
+* Removed the authenticated layout-level `AuthProvider` wrapper and deleted the unused provider/context file. `AppShell` remains the only authenticated session recovery and route-guard owner for dashboard routes.
+* Login and existing-session checks now use the shared profile resource instead of calling `getUserProfile()` directly, so login-to-dashboard can reuse the profile cache that was already fetched for language redirect decisions.
+* Successful email login clears the shared data cache before storing the new session to avoid carrying authenticated resource data across account changes.
+
+## Verification - 2026-05-10 Third Pass
+
+* `npm exec astro sync` in `web/`: passed.
+* `npm exec tsc -- --noEmit` in `web/`: passed.
+* `npm exec astro check` in `web/`: passed with 0 errors; remaining diagnostics are hints.
+* `npm run build` in `web/`: passed. Vite reported the existing `auth.ts` mixed static/dynamic import chunking warning.
+* `git diff --check`: passed.
+
+## Implementation Notes - 2026-05-10 Fourth Pass
+
+* Fresh email-code login submit now redirects using the locale implied by the submitted backend language (`localeToBackendLanguage(locale)` -> `backendLanguageToLocale(language)`) instead of fetching profile before navigation. This removes the avoidable profile GET whose in-memory cache was discarded by the full-page dashboard load.
+* Existing-auth login-page recovery still fetches profile after token refresh because the stored profile language preference is the authoritative source for redirecting an already-authenticated user from the login page. The current resource layer is intentionally in-memory only, so it cannot provide a reload-safe handoff for `window.location.href`; optimizing the fresh-login side avoids the waste while preserving stored-preference redirects for recovered sessions.
+
+## Verification - 2026-05-10 Fourth Pass
+
+* `npm exec tsc -- --noEmit` in `web/`: passed.
+* `npm exec astro check` in `web/`: passed with 0 errors; remaining diagnostics are hints.
+* `npm run build` in `web/`: passed. Vite reported the existing `auth.ts` mixed static/dynamic import chunking warning.
+* `git diff --check`: passed.