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>

dashboard/package-lock.json

@@ -13,6 +13,8 @@
         "workbox-window": "^7.4.0"
       },
       "devDependencies": {
+        "@axe-core/playwright": "^4.11.2",
+        "@playwright/test": "^1.59.1",
         "typescript": "^5.6.3",
         "vite": "^5.4.10",
         "vite-plugin-pwa": "^1.2.0",
@@ -36,6 +38,19 @@
         "ajv": ">=8"
       }
     },
+    "node_modules/@axe-core/playwright": {
+      "version": "4.11.2",
+      "resolved": "https://registry.npmjs.org/@axe-core/playwright/-/playwright-4.11.2.tgz",
+      "integrity": "sha512-iP6hfNl9G0j/SEUSo8M7D80RbcDo9KRAAfDP4IT5OHB+Wm6zUHIrm8Y51BKI+Oyqduvipf9u1hcRy57zCBKzWQ==",
+      "dev": true,
+      "license": "MPL-2.0",
+      "dependencies": {
+        "axe-core": "~4.11.3"
+      },
+      "peerDependencies": {
+        "playwright-core": ">= 1.0.0"
+      }
+    },
     "node_modules/@babel/code-frame": {
       "version": "7.29.0",
       "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.29.0.tgz",
@@ -2037,6 +2052,22 @@
         "@lit-labs/ssr-dom-shim": "^1.5.0"
       }
     },
+    "node_modules/@playwright/test": {
+      "version": "1.59.1",
+      "resolved": "https://registry.npmjs.org/@playwright/test/-/test-1.59.1.tgz",
+      "integrity": "sha512-PG6q63nQg5c9rIi4/Z5lR5IVF7yU5MqmKaPOe0HSc0O2cX1fPi96sUQu5j7eo4gKCkB2AnNGoWt7y4/Xx3Kcqg==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "playwright": "1.59.1"
+      },
+      "bin": {
+        "playwright": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/@preact/signals-core": {
       "version": "1.14.1",
       "resolved": "https://registry.npmjs.org/@preact/signals-core/-/signals-core-1.14.1.tgz",
@@ -2753,6 +2784,16 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/axe-core": {
+      "version": "4.11.3",
+      "resolved": "https://registry.npmjs.org/axe-core/-/axe-core-4.11.3.tgz",
+      "integrity": "sha512-zBQouZixDTbo3jMGqHKyePxYxr1e5W8UdTmBQ7sNtaA9M2bE32daxxPLS/jojhKOHxQ7LWwPjfiwf/fhaJWzlg==",
+      "dev": true,
+      "license": "MPL-2.0",
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/babel-plugin-polyfill-corejs2": {
       "version": "0.4.17",
       "resolved": "https://registry.npmjs.org/babel-plugin-polyfill-corejs2/-/babel-plugin-polyfill-corejs2-0.4.17.tgz",
@@ -4695,6 +4736,53 @@
         "url": "https://github.com/sponsors/jonschlinkert"
       }
     },
+    "node_modules/playwright": {
+      "version": "1.59.1",
+      "resolved": "https://registry.npmjs.org/playwright/-/playwright-1.59.1.tgz",
+      "integrity": "sha512-C8oWjPR3F81yljW9o5OxcWzfh6avkVwDD2VYdwIGqTkl+OGFISgypqzfu7dOe4QNLL2aqcWBmI3PMtLIK233lw==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "playwright-core": "1.59.1"
+      },
+      "bin": {
+        "playwright": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "optionalDependencies": {
+        "fsevents": "2.3.2"
+      }
+    },
+    "node_modules/playwright-core": {
+      "version": "1.59.1",
+      "resolved": "https://registry.npmjs.org/playwright-core/-/playwright-core-1.59.1.tgz",
+      "integrity": "sha512-HBV/RJg81z5BiiZ9yPzIiClYV/QMsDCKUyogwH9p3MCP6IYjUFu/MActgYAvK0oWyV9NlwM3GLBjADyWgydVyg==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "playwright-core": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/playwright/node_modules/fsevents": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
+      "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
+      "dev": true,
+      "hasInstallScript": true,
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
+      }
+    },
     "node_modules/possible-typed-array-names": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/possible-typed-array-names/-/possible-typed-array-names-1.1.0.tgz",