fix(deps): bump nanoid and js-yaml out of two HIGH advisories (#1013)

Both are production dependencies of the backend image (npm ci --omit=dev):

- nanoid 3.3.16 -> 3.3.18 (CVE-2026-67213, infinite loop in customAlphabet), transitive via postcss
- js-yaml 4.3.0 -> 4.3.1 (GHSA-5p4m-2wfm-xmqj, quadratic CPU in !!omap resolution), direct dependency

Lockfile-only; the existing ^ ranges already permitted both fixes. Clears the two open Trivy code-scanning alerts on main.

backend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "picpeak-backend",
-  "version": "3.99.0-beta.0",
+  "version": "3.101.3-beta.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "picpeak-backend",
-      "version": "3.99.0-beta.0",
+      "version": "3.101.3-beta.0",
       "dependencies": {
         "@aws-sdk/client-s3": "^3.850.0",
         "@aws-sdk/lib-storage": "^3.850.0",
@@ -7991,9 +7991,9 @@
       "license": "MIT"
     },
     "node_modules/js-yaml": {
-      "version": "4.3.0",
+      "version": "4.3.1",
-      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.3.0.tgz",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.3.1.tgz",
-      "integrity": "sha512-1td788aAnnZ5qs7V2QIRl1owjtYpbKt749Y3xauqQgwIIGF/xXWz1wMTEBx5O3LK3lXLVuqXPdPxj2BoFHaW9Q==",
+      "integrity": "sha512-CY6crGq313MX8GkwvB7tzgp99vjQxY1++5y10/BKN/GUfHqWaOGQMNZkBvqSzsZKWk/ijwHlWzzkLulsGHhjWQ==",
       "funding": [
         {
           "type": "github",
@@ -9086,9 +9086,9 @@
       }
     },
     "node_modules/nanoid": {
-      "version": "3.3.16",
+      "version": "3.3.18",
-      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.16.tgz",
+      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.18.tgz",
-      "integrity": "sha512-bzlKTyNJ7+LdGIIwy8ijFpIqEQIvafahV7eYykJ8Cvh42EdJeODoJ6gUJXpQJvej1BddH8OqTXZNE/KfbWAu8Q==",
+      "integrity": "sha512-DTg4MJbGMWkfi6VZFdNt2/caMbQy4Ou+Op/hJQvGEWcnVfoA1QA+xzRKAzw9jD6+GVOOeYr/mIcuDSdug6F6+w==",
       "funding": [
         {
           "type": "github",