feat(nvsim): server + onboarding + PWA + GH Pages workflow [ADR-092]

Rounds out the dashboard surface introduced in 39ec05edc with all four
remaining ADR-092 deliverables, plus a deploy workflow that publishes
the SPA to gh-pages/nvsim/ without disturbing the existing observatory
or pose-fusion demos.

## nvsim-server (ADR-092 §6.2)

New crate `v2/crates/nvsim-server`. Axum host fronting nvsim::Pipeline:

- REST control plane (15 routes) — /api/health, /api/scene, /api/config,
  /api/seed, /api/run, /api/pause, /api/reset, /api/step,
  /api/witness/{generate,verify,reference}, /api/export-proof
- Binary WebSocket data plane at /ws/stream — pushes 32-frame
  MagFrame batches at ~60 Hz tick rate
- /api/witness/verify always runs the canonical Proof::generate so the
  hash matches Proof::EXPECTED_WITNESS_HEX byte-for-byte across WASM
  and WS transports — the determinism contract.
- CORS configurable via --allowed-origin, listens on 127.0.0.1:7878 by
  default, single-binary deployment.

## Onboarding tour (ADR-092 §10 Pass 6)

`<nv-onboarding>` Lit component, 6-step welcome:
  Welcome → Scene canvas → Run → Witness → App Store → Done.
First-run only — persisted via IndexedDB `onboarding-seen` flag.
Re-triggerable via `nv-show-tour` event for the help menu.

## PWA service worker (ADR-092 §9.3)

vite-plugin-pwa wired with workbox-window. autoUpdate registration,
8 MB precache budget, app-shell + WASM caching:
- manifest.webmanifest with /RuView/nvsim/ scope
- icon-192.svg + icon-512.svg in dashboard/public/
- 16 precache entries / 302 KiB

Verified production build under NVSIM_BASE=/RuView/nvsim/:
  dist/index.html → /RuView/nvsim/assets/...
  dist/manifest.webmanifest → scope: /RuView/nvsim/
  dist/sw.js + workbox-*.js generated cleanly

## GitHub Pages deploy workflow

`.github/workflows/dashboard-pages.yml`:
- Triggers on push to main affecting dashboard/ or v2/crates/nvsim/
- Builds wasm-pack release → npm ci → vite build with prod base path
- Deploys to gh-pages/nvsim/ via peaceiris/actions-gh-pages@v4 with
  keep_files: true — preserves observatory/, pose-fusion/, and the
  root index.html landing page

After first run, the dashboard will be live at:
  https://ruvnet.github.io/RuView/nvsim/

Validated end-to-end with `npx agent-browser`:
- Onboarding modal renders on first visit
- Workspace `cargo check --workspace` clean (1 warning in unrelated
  sensing-server, no nvsim-server warnings after dead-code prune)
- Production build passes with correct base path resolution and
  PWA manifest scope

Co-Authored-By: claude-flow <ruv@ruv.net>

.github/workflows/dashboard-pages.yml

@@ -0,0 +1,85 @@
+name: nvsim Dashboard → GitHub Pages
+
+# Deploys the nvsim Vite/Lit dashboard to gh-pages/nvsim/ — preserving
+# the existing observatory/, pose-fusion/, and root index.html demos
+# already published from gh-pages. ADR-092 §9.
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'v2/crates/nvsim/**'
+      - 'dashboard/**'
+      - '.github/workflows/dashboard-pages.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+concurrency:
+  group: dashboard-pages
+  cancel-in-progress: true
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout main
+        uses: actions/checkout@v4
+
+      - name: Install Rust + wasm32 target
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32-unknown-unknown
+
+      - name: Cache cargo registry
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            v2/target
+          key: ${{ runner.os }}-cargo-nvsim-${{ hashFiles('v2/Cargo.lock') }}
+          restore-keys: ${{ runner.os }}-cargo-nvsim-
+
+      - name: Install wasm-pack
+        run: cargo install wasm-pack --locked --version 0.13.x || true
+
+      - name: Build nvsim WASM
+        working-directory: v2
+        run: |
+          wasm-pack build crates/nvsim \
+            --target web \
+            --out-dir ../../dashboard/public/nvsim-pkg \
+            --release \
+            -- --no-default-features --features wasm
+
+      - name: Setup Node 20
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          cache-dependency-path: dashboard/package-lock.json
+
+      - name: Install dashboard deps
+        working-directory: dashboard
+        run: npm ci
+
+      - name: Build dashboard
+        working-directory: dashboard
+        env:
+          NVSIM_BASE: /RuView/nvsim/
+        run: npm run build
+
+      - name: Deploy to gh-pages/nvsim/
+        uses: peaceiris/actions-gh-pages@v4
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./dashboard/dist
+          destination_dir: nvsim
+          # CRITICAL: preserves observatory/, pose-fusion/, root index.html
+          # and any other RuView demos already on gh-pages.
+          keep_files: true
+          commit_message: 'deploy(nvsim): ${{ github.sha }}'
+          user_name: 'github-actions[bot]'
+          user_email: 'github-actions[bot]@users.noreply.github.com'