#1113 Apply npm audit fix updates excluding KaTeX

Apply the lockfile updates from npm audit fix, including compatible dependency updates and transitive package deduplication.

Defer the KaTeX upgrade because the extension maintains a custom stylesheet that needs accompanying changes and separate formula layout validation. This PR keeps KaTeX at 0.16.21 and does not claim to resolve all audit findings.

Validation:

• npm ci --offline --no-audit --no-fund
• npm test: 1,099 tests passed
• npm run pretty:check and npm run lint
• Production build with BUILD_PARALLEL=0 BUILD_THREAD=0; required artifacts verified for all four variants
• Pre-commit formatting and lint checks passed

Manual browser extension smoke testing was not completed because no graphical display session was available. External automated review was incomplete: CodeRabbit failed to connect, and the additional reviewer had not returned a result.