build(deps): bump zod in /services/backend in the production group

Bumps the production group in /services/backend with 1 update: [zod](https://github.com/colinhacks/zod).


Updates `zod` from 4.6.2 to 4.6.4
- [Release notes](https://github.com/colinhacks/zod/releases)
- [Commits](https://github.com/colinhacks/zod/compare/v4.6.2...v4.6.4)

---
updated-dependencies:
- dependency-name: zod
  dependency-version: 4.6.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: production
...

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

services/backend/package.json

@@ -32,7 +32,7 @@
     "pino": "^10.3.1",
     "prom-client": "^15.1.3",
     "ws": "^8.21.3",
-    "zod": "^4.6.2"
+    "zod": "^4.6.4"
   },
   "devDependencies": {
     "@biomejs/biome": "^2.5.13",

services/backend/pnpm-lock.yaml

@@ -45,8 +45,8 @@ importers:
         specifier: ^8.21.3
         version: 8.21.3
       zod:
-        specifier: ^4.6.2
+        specifier: ^4.6.4
-        version: 4.6.2
+        version: 4.6.4
     devDependencies:
       '@biomejs/biome':
         specifier: ^2.5.13
@@ -1622,8 +1622,8 @@ packages:
     resolution: {integrity: sha512-LKYU1iAXJXUgAXn9URjiu+MWhyUXHsvfp7mcuYm9dSUKK0/CjtrUwFAxD82/mCWbtLsGjFIad0wIsod4zrTAEQ==}
     engines: {node: '>=0.4'}
 
-  zod@4.6.2:
+  zod@4.6.4:
-    resolution: {integrity: sha512-lh5RCAGFa1Cm2hjtNwLQhSs/AsqdWnTQaBER9fEwN/88pSh7KOtJavtBx/0VlkN/uFd61SwYmljLMDAsHlvzBQ==}
+    resolution: {integrity: sha512-AXSD6hvGdvRjajG/l1cC+d6IrhH+sjmPKtYeQdJIK8MFJl3LyClzS+o/YsVC+zQZPupAaeH5skwwm8YqYH7BqA==}
 
 snapshots:
 
@@ -2879,4 +2879,4 @@ snapshots:
 
   xtend@4.0.2: {}
 
-  zod@4.6.2: {}
+  zod@4.6.4: {}