chore: add package manifest, config source-of-truth and tsconfig

- package.json with pi section (extensions/skills/prompts) and Pi libs as peerDependencies (*)
- config/company.json as the single source of truth (values are TODO, gitHost set)
- tsconfig.json for optional local typecheck

tsconfig.json

@@ -0,0 +1,18 @@
+{
+  "//": "Only for local typecheck of extensions (`npm install` peers first, then `npm run typecheck`). Pi itself runs extensions via jiti and needs no build step.",
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "lib": ["ES2023"],
+    "types": ["node"],
+    "strict": true,
+    "noEmit": true,
+    "skipLibCheck": true,
+    "esModuleInterop": true,
+    "resolveJsonModule": true,
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": false
+  },
+  "include": ["extensions/**/*.ts"]
+}