feat(soak): scaffold tests/soak package

Placeholder runner, tsconfig with @bot alias to tests/e2e/bot,
gitignored .env.stresstest + artifacts. Real behavior follows
in Task 10 onward.

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

tests/soak/tsconfig.json

@@ -0,0 +1,24 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "commonjs",
+    "moduleResolution": "node",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "declaration": false,
+    "sourceMap": true,
+    "outDir": "./dist",
+    "rootDir": ".",
+    "baseUrl": ".",
+    "lib": ["ES2022", "DOM"],
+    "paths": {
+      "@soak/*": ["./*"],
+      "@bot/*": ["../e2e/bot/*"]
+    }
+  },
+  "include": ["**/*.ts"],
+  "exclude": ["node_modules", "dist", "artifacts"]
+}