fix(steam): bump decky-loader to 3.2.6 and pnpm to 10.34.4
- decky-loader 3.2.5-pre1 -> 3.2.6, the stable release of the june 2026 steam-beta errorboundary fix (PR #916)
- pnpm_9 (9.15.9) is CVE-flagged in current nixpkgs (CVE-2026-48995 and friends), eval refuses to proceed
- swap fetchPnpmDeps + nativeBuildInputs from pnpm_9 to pnpm_10 (10.34.4, no known vulnerabilities)
- pnpmDeps hash recomputed for the pnpm 10 fetcher; identical at 3.2.6 (frontend deps unchanged between versions)