Make the CLI usable: help, install, reconciliation output

TL;DR: The CLI has no --help, no installed command, and no visibility into auto-reconciliation — fix all three so a human can actually reach for it day-to-day.

User story

As an infrastructure engineer, I want a real infratomic command with discoverable help, so I don't have to read source or memorize the clojure -Sdeps ... incantation to use it.

Acceptance criteria

• infratomic is a real installed command (wrapper script, packaged as a Nix flake app/package)
• infratomic --help (and no-args) lists every subcommand — passthrough terraform ones plus sync/drift-check — and the --policy-check-url/--sync-url/--drift-url flags
• infratomic sync --help and infratomic drift-check --help explain that subcommand's behavior and exit codes
• infratomic apply --help explains the Policy Check gate and --policy-check-url
• sync's printed summary includes reconciliation actions taken (resource, rule, action) from :reconciliation/* records, not just discovered/updated/drifted counts

How to verify

Run nix run .#infratomic -- --help from a clean checkout — confirm it lists all subcommands without reading source. Run infratomic sync --help. Run infratomic sync against a State Backend with a pending policy-violating resource and confirm the printed summary names the reconciliation action taken on it.

Out of scope

• Compiling a native (GraalVM) binary
• Changing Policy Check/Sync/Drift Check HTTP behavior itself

Start by running nix run .#infratomic -- --help from a clean checkout and inspect the Nix flake app/package and current CLI entry point. Add the installed infratomic command and help for the main and named subcommands, including the listed flags and exit-code behavior. Verify the help output and run infratomic sync against a State Backend to confirm reconciliation actions appear in the summary.