feat: rustc-style --version with git commit and build date

[cs01]

Summary

Makes chad --version useful for bug reports — prints git commit and build date embedded in the version string, rustc-style as a single hyphenated token:

$ chad --version
chad 0.3.0-beta-437cdd99-2026-04-14

Previously chad 0.2.0-beta, which tells you nothing about which build someone is actually running.

Also bumps version 0.2.0-beta → 0.3.0-beta.

How it works

scripts/gen-version.js (the existing prebuild hook) now shells out to git rev-parse --short HEAD and bakes a single VERSION constant of the form <semver>-<sha>-<date> into src/version.ts. If git isn't available (e.g., building from a release tarball), the sha falls back to "unknown".

Kept the single VERSION export — zero touches to src/*.ts, just content changes in the generated src/version.ts.

Test plan

• node dist/chad-node.js --version → chad 0.3.0-beta-<sha>-<date>
• ./.build/chad --version (native compiler) → same
• npm run verify passes — full tests + stage 0/1/2 self-hosting

[github-actions]

Benchmark Results (Linux x86-64)

Benchmark	C	ChadScript	Go	Node	Place
Binary Trees	1.271s	1.555s	2.923s	1.339s	🥉
Cold Start	0.8ms	0.6ms	0.9ms	25.1ms	🥇
Fibonacci	0.725s	0.722s	1.429s	2.831s	🥇
File I/O	0.089s	0.090s	0.089s	0.315s	🥉
JSON Parse/Stringify	0.003s	0.005s	0.017s	0.015s	🥈
Matrix Multiply	0.433s	0.431s	0.456s	0.466s	🥇
Monte Carlo Pi	0.400s	0.381s	0.405s	1.473s	🥇
N-Body Simulation	1.455s	1.855s	1.945s	2.296s	🥈
Quicksort	0.170s	0.216s	0.182s	0.247s	🥉
SQLite	0.309s	0.330s	—	0.412s	🥈
Sieve of Eratosthenes	0.026s	0.040s	0.036s	0.053s	🥉
String Manipulation	0.008s	0.017s	0.017s	0.038s	🥉

CLI Tool Benchmarks

Benchmark	ChadScript	grep	node	xxd	Place
Hex Dump	0.441s	—	1.130s	0.072s	🥈
Recursive Grep	0.010s	0.006s	0.096s	—	🥈