docs: correct stale detection rule and scenario counts in READMEs

[sepehr-safari]

Problem

Both READMEs advertise "10 detection rules" and "10 predefined scenarios". The
source has shipped 16 rules and 15 scenarios since 0.3.1, so the docs undersell
the project's actual capability.

This matters most for packages/toolkit/README.md: that is the file npm renders
on the @ocpp-debugkit/toolkit package page, so the stale counts are the first
thing anyone evaluating the library reads. The root README.md is the GitHub
repo landing page and carries the same two stale lines.

The studio README, the website copy, and the profile README already say 16/15.
These two files are the only holdouts.

Verified against source, not prose

• FailureCode in packages/toolkit/src/core/types.ts has 16 codes.
• SEVERITY in packages/toolkit/src/core/detection.ts splits them
  4 critical / 10 warning / 2 info.
• detectFailures() composes 16 detect* calls.
• scenarios in packages/toolkit/src/scenarios/index.ts exports 15, pinned by
  the existing exports exactly 15 scenarios test.

The 16th rule (REPEATED_BOOT_NOTIFICATION) landed in #114 and shipped in
0.3.1. Both READMEs were last updated before that and never caught up.

Scope

• packages/toolkit/README.md (npm package page): 10 -> 16 rules, 10 -> 15
  scenarios.
• README.md (repo landing page): same two lines.
• CURRENT_STATE.md: "Current Version" reads 0.3.0 (published) but npm latest
  is 0.3.1 (published 2026-07-09); package status table says 0.3.0 too.

Not in scope

The v0.3 milestone blurb in CURRENT_STATE.md says v0.3.0 shipped "15 detection
rules". That is historically accurate for v0.3.0 and stays as a record of that
release; only the current-version fields move to 0.3.1.

The four deprecated 0.1.1 packages (core, scenarios, reporter, cli)
carry an npm deprecation notice pointing at the pre-rename ocpp-debugkit/ocpp-debugkit
URL. That is registry metadata rather than a file in this repo, so it is fixed
with npm deprecate and not by this PR.