fix(deps): bump dompurify to 3.4.9 to fix XSS advisories

dompurify 3.4.0 was affected by several stacked advisories (mXSS /
sanitizer bypasses). 3.4.9 is past all vulnerable ranges. Resolves
Dependabot alerts #248-#254 (package.json) and #259-#265 (lockfile).

frontend/package.json

@@ -82,7 +82,7 @@
     "bulma-css-variables": "0.9.33",
     "change-case": "5.4.4",
     "dayjs": "1.11.19",
-    "dompurify": "3.4.0",
+    "dompurify": "3.4.9",
     "fast-deep-equal": "3.1.3",
     "flatpickr": "4.6.13",
     "floating-vue": "5.2.2",

frontend/pnpm-lock.yaml

@@ -113,8 +113,8 @@ importers:
         specifier: 1.11.19
         version: 1.11.19
       dompurify:
-        specifier: 3.4.0
-        version: 3.4.0
+        specifier: 3.4.9
+        version: 3.4.9
       fast-deep-equal:
         specifier: 3.1.3
         version: 3.1.3
@@ -3569,8 +3569,8 @@ packages:
     resolution: {integrity: sha512-cgwlv/1iFQiFnU96XXgROh8xTeetsnJiDsTc7TYCLFd9+/WNkIqPTxiM/8pSd8VIrhXGTf1Ny1q1hquVqDJB5w==}
     engines: {node: '>= 4'}
 
-  dompurify@3.4.0:
-    resolution: {integrity: sha512-nolgK9JcaUXMSmW+j1yaSvaEaoXYHwWyGJlkoCTghc97KgGDDSnpoU/PlEnw63Ah+TGKFOyY+X5LnxaWbCSfXg==}
+  dompurify@3.4.9:
+    resolution: {integrity: sha512-4dPSRMRDqHvs0V4YDFCsaIZo4if5u0xM+llyxiM2fwuZFdKArUBAF3VtI2+n8NKg9P870WMdYk0UhqQNoWXbfQ==}
 
   domutils@3.2.2:
     resolution: {integrity: sha512-6kZKyUajlDuqlHKVX1w7gyslj9MPIXzIFiz/rGu35uC1wMi+kMhQwGhl4lt9unC9Vb9INnY9Z3/ZA3+FhASLaw==}
@@ -10334,7 +10334,7 @@ snapshots:
     dependencies:
       domelementtype: 2.3.0
 
-  dompurify@3.4.0:
+  dompurify@3.4.9:
     optionalDependencies:
       '@types/trusted-types': 2.0.7