infra: nvsim-server Docker + axe-core cross-browser CI

Closes the infrastructure half of ADR-092's open §11 gates:
- §11.5 axe-core a11y formal scan
- §11.8 cross-browser (Chromium + Firefox + WebKit)

## v2/crates/nvsim-server/Dockerfile (new)

Multi-stage build (rust:1.81-slim → debian:bookworm-slim):
- builds nvsim-server release binary
- runs as non-root `nvsim` user
- exposes 7878
- HEALTHCHECK against /api/health
- ENTRYPOINT nvsim-server with default --listen 0.0.0.0:7878

## .github/workflows/nvsim-server-docker.yml (new)

- triggers: push to main affecting nvsim*, tag nvsim-server-v*, manual
- publishes ghcr.io/ruvnet/nvsim-server:{branch,tag,sha,latest}
- multi-platform: linux/amd64
- post-publish smoke test: docker pull + run + curl /api/health

## dashboard/tests/a11y.spec.ts (new)

Playwright + @axe-core/playwright suite:
- iterates 6 primary views (home/scene/apps/inspector/witness/ghost-murmur)
- dismisses welcome modal, navigates via rail buttons
- runs axe-core with wcag2a + wcag2aa rule sets
- asserts 0 critical AND 0 serious violations per view
- prints violation summary on failure for actionable CI logs

## dashboard/playwright.config.ts (new)

- 3 projects: chromium, firefox, webkit
- webServer: npm run preview (vite preview port 4173)
- baseURL: http://localhost:4173

## .github/workflows/dashboard-a11y.yml (new)

- triggers: push to main, PRs touching dashboard/**, manual
- builds nvsim WASM via wasm-pack
- npm ci + playwright install --with-deps
- npm run build + npx playwright test (all 3 browsers × 6 views)

## dashboard/package.json

- new scripts: test:e2e, test:a11y
- new devDeps: @playwright/test, @axe-core/playwright

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

.github/workflows/dashboard-a11y.yml

@@ -0,0 +1,45 @@
+name: Dashboard a11y + cross-browser
+
+# Runs axe-core a11y assertions on the built dashboard across
+# Chromium, Firefox, and WebKit. Closes ADR-092 §11.5 (axe-core)
+# and §11.8 (cross-browser).
+
+on:
+  push:
+    branches: [main]
+    paths: ['dashboard/**', 'v2/crates/nvsim/**']
+  pull_request:
+    paths: ['dashboard/**']
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  a11y:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: dtolnay/rust-toolchain@stable
+        with: { targets: wasm32-unknown-unknown }
+
+      - 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
+
+      - uses: actions/setup-node@v4
+        with: { node-version: 20, cache: npm, cache-dependency-path: dashboard/package-lock.json }
+
+      - working-directory: dashboard
+        run: |
+          npm ci
+          npm install --save-dev @playwright/test @axe-core/playwright
+          npx playwright install --with-deps
+          npm run build
+          npx playwright test

.github/workflows/nvsim-server-docker.yml

@@ -0,0 +1,69 @@
+name: nvsim-server → ghcr.io
+
+# Builds and publishes the nvsim-server Docker image to ghcr.io on:
+# - push to main affecting nvsim-server or nvsim
+# - tag push matching nvsim-server-v*
+# - manual workflow_dispatch
+#
+# ADR-092 §6.2 + §9.4.
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'v2/crates/nvsim-server/**'
+      - 'v2/crates/nvsim/**'
+      - '.github/workflows/nvsim-server-docker.yml'
+    tags: ['nvsim-server-v*']
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  build-and-publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/setup-buildx-action@v3
+
+      - uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/ruvnet/nvsim-server
+          tags: |
+            type=ref,event=branch
+            type=ref,event=tag
+            type=sha,format=short
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: Build + push
+        uses: docker/build-push-action@v5
+        with:
+          context: v2
+          file: v2/crates/nvsim-server/Dockerfile
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          platforms: linux/amd64
+
+      - name: Smoke-test the image
+        run: |
+          docker pull ghcr.io/ruvnet/nvsim-server:sha-${GITHUB_SHA::7} || \
+            docker pull ghcr.io/ruvnet/nvsim-server:latest
+          docker run --rm -d --name nvsim-test -p 7878:7878 \
+            ghcr.io/ruvnet/nvsim-server:latest
+          sleep 4
+          curl -fsS http://localhost:7878/api/health
+          docker stop nvsim-test