Docs: update Files section to list all CLI tools

[casks-mutters]

Summary

The README's ## Files section currently lists only:

• app.py
• README.md

However, the repository now also includes several additional CLI helpers:

• batch_slot_diff.py
• slot_diff_attest.py
• slot_layout_probe.py
• slot_change_stream.py
• slot_change_finder.py

This mismatch may confuse users browsing the repo or trying to discover available tools.

Changes

• Update the ## Files section in README.md to include all of the main Python entrypoints and a one-line explanation for each:
  • app.py – single-slot, two-block commitment checker (core tool).
  • batch_slot_diff.py – batch CSV processor for many slots/blocks.
  • slot_diff_attest.py – signed JSON attestation generator.
  • slot_layout_probe.py – scan ranges of slots and emit CSV/commitments.
  • slot_change_stream.py – live monitor for slot changes over new blocks.
  • slot_change_finder.py – helper to search for the first block where a slot value changed (if applicable).
• Keep README.md itself listed as the documentation file.

Rationale

• Keeps documentation in sync with the actual repository contents.
• Makes the additional tools discoverable for users who only read the README.
• Helps people quickly pick the right script for their use case (single slot vs batch vs streaming vs layout probing).

Notes

This is a docs-only change; no code behavior is modified.