Add SSR bridge: Django template backend + Bun subprocess renderer

Mizan's SSR is a Django template backend. Configure in TEMPLATES:

    TEMPLATES = [{
        'BACKEND': 'mizan.ssr.MizanTemplates',
        'OPTIONS': {'worker_path': 'frontend/ssr-worker.tsx'},
    }]

Then render(request, 'ProfilePage', {'user_id': 5}) renders the React
component via a persistent Bun subprocess. The component name is the
template name. The context dict becomes props.

Architecture:
- Bun worker: stdin/stdout JSON-RPC, renderToString, component registry
- Django bridge: subprocess lifecycle, crash recovery, concurrent renders
- Template backend: implements Django's BaseEngine interface

This is the AFI's SSR boundary:
- Backend adapter implements mizan.ssr() (data gathering)
- Frontend adapter implements renderToHTML() (component rendering)
- Bun subprocess is the runtime hosting the frontend adapter

11 tests: ping, render, error handling, crash recovery, concurrent
renders (5 threads), template backend integration. All require Bun.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/mizan-ssr/bun.lock

@@ -0,0 +1,37 @@
+{
+  "lockfileVersion": 1,
+  "configVersion": 1,
+  "workspaces": {
+    "": {
+      "name": "@mizan/ssr",
+      "dependencies": {
+        "react": "^19.0.0",
+        "react-dom": "^19.0.0",
+      },
+      "devDependencies": {
+        "@types/react": "^19.0.0",
+        "@types/react-dom": "^19.0.0",
+        "bun-types": "latest",
+      },
+    },
+  },
+  "packages": {
+    "@types/node": ["@types/node@25.5.2", "", { "dependencies": { "undici-types": "~7.18.0" } }, "sha512-tO4ZIRKNC+MDWV4qKVZe3Ql/woTnmHDr5JD8UI5hn2pwBrHEwOEMZK7WlNb5RKB6EoJ02gwmQS9OrjuFnZYdpg=="],
+
+    "@types/react": ["@types/react@19.2.14", "", { "dependencies": { "csstype": "^3.2.2" } }, "sha512-ilcTH/UniCkMdtexkoCN0bI7pMcJDvmQFPvuPvmEaYA/NSfFTAgdUSLAoVjaRJm7+6PvcM+q1zYOwS4wTYMF9w=="],
+
+    "@types/react-dom": ["@types/react-dom@19.2.3", "", { "peerDependencies": { "@types/react": "^19.2.0" } }, "sha512-jp2L/eY6fn+KgVVQAOqYItbF0VY/YApe5Mz2F0aykSO8gx31bYCZyvSeYxCHKvzHG5eZjc+zyaS5BrBWya2+kQ=="],
+
+    "bun-types": ["bun-types@1.3.11", "", { "dependencies": { "@types/node": "*" } }, "sha512-1KGPpoxQWl9f6wcZh57LvrPIInQMn2TQ7jsgxqpRzg+l0QPOFvJVH7HmvHo/AiPgwXy+/Thf6Ov3EdVn1vOabg=="],
+
+    "csstype": ["csstype@3.2.3", "", {}, "sha512-z1HGKcYy2xA8AGQfwrn0PAy+PB7X/GSj3UVJW9qKyn43xWa+gl5nXmU4qqLMRzWVLFC8KusUX8T/0kCiOYpAIQ=="],
+
+    "react": ["react@19.2.4", "", {}, "sha512-9nfp2hYpCwOjAN+8TZFGhtWEwgvWHXqESH8qT89AT/lWklpLON22Lc8pEtnpsZz7VmawabSU0gCjnj8aC0euHQ=="],
+
+    "react-dom": ["react-dom@19.2.4", "", { "dependencies": { "scheduler": "^0.27.0" }, "peerDependencies": { "react": "^19.2.4" } }, "sha512-AXJdLo8kgMbimY95O2aKQqsz2iWi9jMgKJhRBAxECE4IFxfcazB2LmzloIoibJI3C12IlY20+KFaLv+71bUJeQ=="],
+
+    "scheduler": ["scheduler@0.27.0", "", {}, "sha512-eNv+WrVbKu1f3vbYJT/xtiF5syA5HPIMtf9IgY/nKg0sWqzAUEvqY/xm7OcZc/qafLx/iO9FgOmeSAp4v5ti/Q=="],
+
+    "undici-types": ["undici-types@7.18.2", "", {}, "sha512-AsuCzffGHJybSaRrmr5eHr81mwJU3kjw6M+uprWvCXiNeN9SOGwQ3Jn8jb8m3Z6izVgknn1R0FTCEAP2QrLY/w=="],
+  }
+}