Vulnerability remediation

[kflemin]

• pnpm update: patched versions for undici, immutable, postcss, lodash, flatted, nanoid, brace-expansion, vite (bumped @angular/build/@angular/cli 21.2.5→21.2.24 and related dev tooling within semver).
• Replaced decompress (abandoned, zip-slip) with adm-zip in update-translations.mts, the only usage (dev-only Lokalise sync script); reimplemented strip: 1 plus a path-traversal guard.
• Added pnpm.overrides forcing less@^4.9.1 (transitive optional peer dep of @angular/build/vite), which drops image-size@0.5.5 entirely in favor of probe-image-size.
• Fixed 8 files failing lint under the newer typescript-eslint (no-unnecessary-type-assertion), a side effect of the update.