v0.2 Phase 0+1: planning doc + tooling baseline

Phase 0 — docs/release/v0.2-frontend-overhaul.md as single source of
truth for the v0.2 frontend coherence pass. Records hard rules,
tooling pins, sacred-behaviour contract list, wrapper catalogue,
per-page migration order, verification matrix, KI-05 plan, and the
explicit "DO NOT add Skeleton" line.

Phase 1 — tooling baseline. All exact-pinned per the plan:

- @playwright/test@1.60.0 + playwright@1.60.0 + @axe-core/playwright@4.11.3
- rollup-plugin-visualizer@7.0.1 (wired behind ANALYZE=1)
- @vitest/browser@4.1.6 + @vitest/browser-playwright@4.1.6 (provider)
- vitest-browser-svelte@2.1.1 (runes-aware Svelte 5 bridge)
- cargo-nextest installed globally

New configs: playwright.config.ts (frontend-only, dev:frontend webServer,
900x700 + 1440x900 projects, visual baselines deferred), vitest.browser.config.js
(separate from jsdom suite). New scripts: test:e2e, test:e2e:ui,
test:browser, analyze, test:rust:fast, guard:no-skeleton.

guard-no-skeleton.mjs walks package.json + package-lock + src/ for any
@skeletonlabs reference and exits 1 if found — locks in the no-Skeleton
hard rule for any future agent.

Smoke baseline (tests/e2e/smoke.spec.ts): 16 tests passing across two
viewports — app loads without Tauri runtime, keyboard nav, axe scan
(color-contrast deferred to Phase 7 per docs/release/v0.1-contrast-audit.md),
light/dark theme cycle, all three sensory zones (cave/energy/reset).
10 screenshots emitted to test-results/ as non-failing artefacts.

Surfaced + fixed two browser-preview bugs while landing the baseline:

- src/lib/utils/osInfo.ts: FALLBACK_BROWSER_INFO was evaluated at SSR
  module-load (navigator undefined → os: 'unknown'), and the UA check
  ran before navigator.platform — so Playwright's Windows-UA Chromium
  on a Linux runner detected as Windows, useCustomChrome went true,
  Titlebar mounted and tripped Tauri-only APIs. Now lazy-built per
  call; platform is the primary signal, UA only a fallback.

- src/lib/components/Titlebar.svelte: defensive hasTauriRuntime() guard
  on every handler and the $effect. Titlebar should not crash if any
  future code path mounts it without Tauri.

.gitignore: reports/, .playwright/, test-results/, playwright-report/.

Per-phase gate green: npm run check (0/0), npm test (0/0), npm run
test:e2e (16/16), npm run guard:no-skeleton (clean).

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

src/lib/components/Titlebar.svelte

@@ -1,33 +1,48 @@
 <script lang="ts">
   import { getCurrentWindow } from "@tauri-apps/api/window";
   import { settings } from "$lib/stores/page.svelte.js";
+  import { hasTauriRuntime } from "$lib/utils/runtime.js";
 
   let { compact = false } = $props();
 
   let maximised = $state(false);
 
+  // Titlebar is normally gated behind useCustomChrome in the route layouts,
+  // which is false on Linux (native KWin/Mutter decorations) and false in
+  // any browser-preview context that mis-detects the OS. The defensive
+  // guard here keeps the component from crashing in any future code path
+  // that mounts it without a Tauri runtime — `getCurrentWindow()` reads
+  // window.__TAURI_INTERNALS__.metadata which is undefined in plain browsers.
+  const tauriPresent = hasTauriRuntime();
+
   async function handleMinimise() {
+    if (!tauriPresent) return;
     await getCurrentWindow().minimize();
   }
 
   async function handleMaximise() {
+    if (!tauriPresent) return;
     await getCurrentWindow().toggleMaximize();
     maximised = await getCurrentWindow().isMaximized();
   }
 
   async function handleClose() {
+    if (!tauriPresent) return;
     await getCurrentWindow().hide();
   }
 
   function handleDragStart(e: PointerEvent) {
+    if (!tauriPresent) return;
     if (e.button !== 0) return;
     if ((e.target as HTMLElement | null)?.closest("button")) return;
     try { (e.currentTarget as HTMLElement | null)?.setPointerCapture?.(e.pointerId); } catch {}
     getCurrentWindow().startDragging();
   }
 
-  // Track maximise state
+  // Track maximise state. Skipped without Tauri; getCurrentWindow().onResized
+  // throws because the underlying Window object has no `metadata`.
   $effect(() => {
+    if (!tauriPresent) return;
     let unlisten: (() => void) | undefined;
     getCurrentWindow().onResized(async () => {
       maximised = await getCurrentWindow().isMaximized();