feat: extract auth into @marketplaces/auth package, add backoffice admin provisioning spec

- ADR-0001: decision to extract auth/payment into shared @marketplaces/* packages
- Scaffold packages/auth, packages/payment; @marketplaces/auth now holds the real
  telegram (customer+admin QR/session) and ed25519 (future admin challenge/response)
  auth implementation, pushed to sources.vitanova.network/sdarbinyan/vitanovaPackages
- Rewire ~30 call sites to import from @marketplaces/auth; delete migrated originals
  from core/auth, core/admin-auth, services/, models/
- Replace environment coupling with AUTH_API_URL/TELEGRAM_BOT_USERNAME injection
  tokens and isDevMode(); wired as file:packages/auth pending registry publish
- Add TRACK-S §8: bootstrap per-marketplace admin login + marketplace-scoped
  sub-admin invite/role endpoints
- Build, arch:check:boundaries, and full test suite (103/103) all green

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

packages/auth/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "@marketplaces/auth",
+  "version": "0.1.0",
+  "description": "Shared customer + admin auth client (VK ID/OTP/session, ed25519 admin verification, guards, interceptors) for marketplaces projects.",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "files": ["dist"],
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "test": "echo \"no tests yet\" && exit 0"
+  },
+  "peerDependencies": {
+    "@angular/core": ">=22.0.0",
+    "@angular/common": ">=22.0.0",
+    "rxjs": ">=7.8.0"
+  },
+  "publishConfig": {
+    "access": "restricted"
+  },
+  "license": "UNLICENSED"
+}