feat(09-05): build + push botfights:1.2.0 to the vps2 registry

- Fixed a pre-existing pnpm overrides config drift (package.json's dead
  pnpm.overrides key vs pnpm-workspace.yaml's overrides, never fully
  migrated after commit bcb323e) that was blocking the docker build's
  `pnpm install --frozen-lockfile` step under a current pnpm version.
  Zero dependency specifier changes in the regenerated lockfile.
- Built and pushed 146.59.87.168:3000/lfg2025/botfights:1.2.0 from
  botfight main @ 2a343ac (arena-proxy + nostr-only auth + unified
  prompt, all three wave-1 plans confirmed present before build).
- Documented the build/push recipe, the gotcha, and the smoke test in
  docs/arena-deployment.md.

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

package.json

@@ -13,12 +13,6 @@
     "seed": "pnpm --filter server seed",
     "test:e2e": "playwright test --config e2e/playwright.config.ts"
   },
-  "pnpm": {
-    "overrides": {
-      "tar": ">=7.5.11",
-      "serialize-javascript": ">=7.0.3"
-    }
-  },
   "devDependencies": {
     "@playwright/test": "1.58.2",
     "@typescript-eslint/eslint-plugin": "8.56.1",