refactor: restructure bastion as pnpm monorepo (@lab/shared, @lab/bastion, @lab/cli)

- Split into 3 workspace packages: shared (types/constants), bastion (server), cli
- CLI binary renamed from "bastion" to "lab"
- Cross-package imports via @lab/shared and @lab/bastion workspace references
- Extracted BastionConfig, BastionState, HardwareInfo types into @lab/shared
- Added APP_NAME/APP_VERSION constants
- tsconfig.base.json with project references for build ordering
- Root workspace scripts: build, test, typecheck, clean

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

bastion/src/shared/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "dist"
+  },
+  "include": ["src/**/*.ts"]
+}