fix anchor test with TypeScript

[AuroraLantean]

resolve TypeScript error when running "anchor test"
resolve compilation warning when running "anchor build"

[zkr99]

Good progress — the import type and .accountsStrict() changes are solid improvements, please keep those.

For this PR, let's revert the toolchain-level changes to keep the build stable during the hackathon sprint:

• "type": "module" in package.json and module: "esnext" in tsconfig (the ESM migration pulls in the fileURLToPath / import.meta.url changes too — all of that can come out)
• @types/node version bump
• #![allow(unexpected_cfgs)] on the Rust files — those warnings come from Anchor's derive macros, not our code, so they're safe to leave as-is

Once that's cleaned up this is good to merge. After that, the next high-value deliverable is the compute budget analysis — measuring actual CU consumed per instruction across all 3 programs. That data feeds directly into the transaction batching work we just shipped.