chore(deps): bump flatted to 3.4.2

[bntvllnt]

Summary

• Supersedes stale Dependabot PR chore(deps): bump flatted from 3.3.4 to 3.4.1 in the npm_and_yarn group across 1 directory #9 by bumping the transitive flatted lockfile resolution from 3.3.4 to 3.4.2.
• Leaves the change intentionally narrow: pnpm-lock.yaml only.

Security / audit

• Addresses advisory 1115357 / GHSA-rf6f-7fwh-wjgh for flatted (<=3.4.1, patched >=3.4.2).
• Fresh pnpm audit --audit-level=moderate --json no longer reports advisory 1115357.
• Audit still exits non-zero because unrelated advisories remain in the lockfile; this PR should be treated as a narrow superseding remediation for chore(deps): bump flatted from 3.3.4 to 3.4.1 in the npm_and_yarn group across 1 directory #9, not a full dependency-audit cleanup.

Validation

• pnpm install --frozen-lockfile passed.
• pnpm lint passed.
• pnpm test:once passed: 5 files / 119 tests.
• pnpm audit --audit-level=moderate --json ran and exits 1 with 25 remaining non-flatted advisories.

Review gate

• No auto-merge.
• Do not merge chore(deps): bump flatted from 3.3.4 to 3.4.1 in the npm_and_yarn group across 1 directory #9 as-is; it only updates flatted to 3.4.1, which remains vulnerable.

[greptile-apps]

No reviewable files after applying ignore patterns.