chore: set up pnpm workspace tooling

Root package.json with workspace scripts, pnpm-workspace.yaml, shared
tsconfig base, ESLint flat config, Prettier, editorconfig, .nvmrc, and
.env.example covering LiveKit/Gemini/GitHub/Atlas/Voyage.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package.json

@@ -0,0 +1,29 @@
+{
+  "name": "podman",
+  "version": "0.0.0",
+  "private": true,
+  "description": "Ambient AI teammate that prevents merge collisions before code is pushed",
+  "type": "module",
+  "packageManager": "pnpm@10.32.1",
+  "engines": {
+    "node": ">=22"
+  },
+  "scripts": {
+    "dev": "pnpm -r --parallel dev",
+    "dev:frontend": "pnpm --filter @podman/frontend dev",
+    "dev:backend": "pnpm --filter @podman/backend dev",
+    "build": "pnpm -r build",
+    "typecheck": "pnpm -r typecheck",
+    "lint": "eslint .",
+    "format": "prettier --write .",
+    "format:check": "prettier --check ."
+  },
+  "devDependencies": {
+    "@eslint/js": "^10.0.1",
+    "@types/node": "^26.0.1",
+    "eslint": "^10.6.0",
+    "prettier": "^3.9.0",
+    "typescript": "^6.0.3",
+    "typescript-eslint": "^8.62.0"
+  }
+}