feat: set up monorepo scaffold with Yarn workspaces, Django API, React/Vite web, and Docker Compose

- Root package.json with Yarn workspaces (web, api)
- /web: React 19 + Vite 6 + @vitejs/plugin-react
  - index.html, src/main.jsx, src/App.jsx, vite.config.js
- /api: Django 5.x managed with uv
  - pyproject.toml with Django + psycopg2-binary
  - project/settings.py with PostgreSQL config from DATABASE_URL
  - project/urls.py, project/wsgi.py, manage.py
- docker-compose.yml with db (postgres:15), api, web services
  - Health check for db, live code volumes, dependency ordering
- Dockerfiles for both web (node:20-alpine) and api (python:3.12-slim)
- .gitignore updated for Python build artifacts and venv
- docs/implementation-issue-1-monorepo-scaffold.md

yarn.lock

@@ -0,0 +1,20 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+react-dom@^19.0.0:
+  version "19.2.6"
+  resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-19.2.6.tgz#44a81b0bcca22da814c00847d09d01c8615529b7"
+  integrity sha512-0prMI+hvBbPjsWnxDLxlCGyM8PN6UuWjEUCYmZhO67xIV9Xasa/r/vDnq+Xyq4Lo27g8QSbO5YzARu0D1Sps3g==
+  dependencies:
+    scheduler "^0.27.0"
+
+react@^19.0.0:
+  version "19.2.6"
+  resolved "https://registry.yarnpkg.com/react/-/react-19.2.6.tgz#3dadb8e12b2a7934c1d5317973e5dce1301f9a4d"
+  integrity sha512-sfWGGfavi0xr8Pg0sVsyHMAOziVYKgPLNrS7ig+ivMNb3wbCBw3KxtflsGBAwD3gYQlE/AEZsTLgToRrSCjb0Q==
+
+scheduler@^0.27.0:
+  version "0.27.0"
+  resolved "https://registry.yarnpkg.com/scheduler/-/scheduler-0.27.0.tgz#0c4ef82d67d1e5c1e359e8fc76d3a87f045fe5bd"
+  integrity sha512-eNv+WrVbKu1f3vbYJT/xtiF5syA5HPIMtf9IgY/nKg0sWqzAUEvqY/xm7OcZc/qafLx/iO9FgOmeSAp4v5ti/Q==