fix(npx): use npx (not npm) for unrecognized npx commands

[lineardevon]

Summary

• The Commands::Npx catch-all fallback called npm_cmd::run(), which invoked npm instead of npx
• When npx flags preceded the tool name (e.g. npx -y -p @playwright/cli playwright-cli list), routing fell to the catch-all and ran the wrong binary
• Replace with direct npx passthrough matching the existing prisma passthrough pattern

Fixes #713

Test plan

• cargo fmt --all && cargo clippy --all-targets && cargo test (1056 passed on develop)
• Manual testing: verified rtk npx tsc --version and rtk npx playwright test still route to specialized handlers
• Verified existing passthrough pattern consistency (prisma at lines 1933-1946)

Note: Flag-aware routing (npx -y tsc → tsc_cmd) and rewrite-layer regex updates are follow-up opportunities.

[CLAassistant]

All committers have signed the CLA.

[aeppling]

Hey

We are cleaning up the codebase and improving the project structure for better onboarding. As part of this effort, PR #826 reorganizes src/ from a flat layout into subfolders.

No logic changes — only file moves and import path updates.

What you need to do

Rebase your branch on develop when receiving this comment:

git fetch origin && git rebase origin/develop

Git detects renames automatically. If you get import conflicts, update the paths:

use crate::git;        // now: use crate::cmds::git::git;
use crate::tracking;   // now: use crate::core::tracking;
use crate::config;     // now: use crate::core::config;
use crate::init;       // now: use crate::hooks::init;
use crate::gain;       // now: use crate::analytics::gain;

Need help rebasing? Tag @aeppling

[KuSh]

Closing as #1458 has taken care of the problem