feat(01-01): monorepo scaffold with root configs and shared package

- Root package.json with pnpm workspace, Turborepo, Biome, TypeScript
- pnpm-workspace.yaml defining apps/* and packages/* workspaces
- turbo.json with build, dev, lint, type-check task definitions
- tsconfig.base.json with strict mode and bundler module resolution
- biome.json with formatter and linter configuration
- .gitignore, .env.example, .dockerignore
- @tessera/shared package with APP_NAME constant and HealthResponse type
- pnpm-lock.yaml generated from successful install

biome.json

@@ -0,0 +1,18 @@
+{
+  "$schema": "https://biomejs.dev/schemas/2.5.0/schema.json",
+  "organizeImports": {
+    "enabled": true
+  },
+  "formatter": {
+    "enabled": true,
+    "indentStyle": "space",
+    "indentWidth": 2,
+    "lineWidth": 100
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true
+    }
+  }
+}