chore(deps): bump dompurify override to >=3.4.5 (GHSA-87xg-pxx2-7hvx)

dompurify@3.4.4 is vulnerable to XSS via the selectedcontent re-clone
path (GHSA-87xg-pxx2-7hvx). dompurify is transitive via mermaid; the
latest mermaid (11.15.0) declares dompurify@^3.3.1 — that range still
permits 3.4.4 so an upstream bump does not move us off the vulnerable
version. Add an override matching the existing pattern for axios /
tmp / esbuild / etc.

Resolved version after install: dompurify@3.4.7. Patch-range bump
on a sanitisation-only library — risk minimal.

package.json

@@ -45,6 +45,7 @@
       "axios@<1.15.2": ">=1.15.2",
       "@angular-devkit/core>ajv@<8.18.0": ">=8.18.0",
       "brace-expansion@<5.0.6": ">=5.0.6",
+      "dompurify@<3.4.5": ">=3.4.5",
       "esbuild@<0.25.0": ">=0.25.0",
       "follow-redirects@<1.16.0": ">=1.16.0",
       "ip-address@<10.1.1": ">=10.1.1",