build(deps): Bump zod from 3.25.76 to 4.3.6

Bumps [zod](https://github.com/colinhacks/zod) from 3.25.76 to 4.3.6.
- [Release notes](https://github.com/colinhacks/zod/releases)
- [Commits](colinhacks/zod@v3.25.76...v4.3.6)

---
updated-dependencies:
- dependency-name: zod
  dependency-version: 4.3.6
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

packages/backend/package.json

@@ -30,7 +30,7 @@
     "jose": "^6.1.3",
     "pino": "^10.1.0",
     "postgres": "^3.4.5",
-    "zod": "^3.24.0"
+    "zod": "^4.3.6"
   },
   "devDependencies": {
     "@types/bun": "^1.2.0",

packages/frontend/package.json

@@ -24,7 +24,7 @@
     "react-router": "^7.13.0",
     "reactflow": "^11.11.4",
     "tailwind-merge": "^3.4.0",
-    "zod": "^3.24.0",
+    "zod": "^4.3.6",
     "zustand": "^5.0.0"
   },
   "devDependencies": {

packages/shared/package.json

@@ -22,7 +22,7 @@
     "drizzle-orm": "^0.44.0",
     "drizzle-zod": "^0.7.0",
     "postgres": "^3.4.5",
-    "zod": "^3.24.0"
+    "zod": "^4.3.6"
   },
   "devDependencies": {
     "drizzle-kit": "^0.31.0",