feat: add altimate-code check CLI command for deterministic SQL checks

Add a new `check` subcommand that runs deterministic SQL analysis
(lint, validate, safety, policy, PII, semantic, grade) without
requiring an LLM. The command:

- Accepts SQL files as positional args or globs (defaults to `**/*.sql`)
- Calls `Dispatcher.call()` for each check category (no direct napi imports)
- Processes files in batches of 10 for concurrency
- Supports `--format json|text`, `--severity`, `--fail-on` flags
- Outputs diagnostics to stderr, structured JSON to stdout
- Does NOT call `bootstrap()` — no session/db/server needed
- Registered in `index.ts` with proper `altimate_change` markers

Author: anandgupta42