fix(llm-client): move zod to dependencies for Docker builds

The zod package was listed as peerDependency which isn't automatically
installed in Docker production builds. Moving it to regular dependencies
ensures the package builds correctly in CI.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/llm-client/package.json

@@ -37,15 +37,14 @@
     "schema",
     "validation"
   ],
-  "dependencies": {},
-  "peerDependencies": {
-    "zod": "^4.0.0"
+  "dependencies": {
+    "zod": "^4.1.12",
+    "zod-to-json-schema": "^3.24.5"
   },
   "devDependencies": {
     "@types/node": "^20.0.0",
     "typescript": "^5.0.0",
-    "vitest": "^1.0.0",
-    "zod": "^4.1.12"
+    "vitest": "^1.0.0"
   },
   "author": "Soroban Flashcards Team",
   "license": "MIT",