Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@helm/charts/nico-machine-a-tron/README.md`:
- Around line 47-51: Restore the TOML code-fence boundaries in
helm/charts/nico-machine-a-tron/README.md: at lines 47-51, open a toml fence
before [site_explorer] and close it after override_target_port; at lines
235-236, open a toml fence before [networks.pod-0-oob] and close it after the
final gateway. Ensure subsequent Markdown sections render normally.
- Around line 367-375: Update the troubleshooting section in the README by
changing the “Check service selector” and “Check pod labels” headings to
lower-level headings that remain nested under the parent section. Wrap each
kubectl command in its own closed bash code fence, keeping the existing commands
and making the Markdown structure render correctly.

In `@helm/charts/nico-machine-a-tron/templates/configmap.yaml`:
- Line 36: Update the $hwMacBasePrefix fallback in the ConfigMap template from
the single-octet "06" value to the documented two-octet default "02:01",
matching values.yaml and producing valid hardware address prefixes when
basePrefix is absent.
- Around line 54-60: Validate the computed $podIndex after the podList lookup
and fail template rendering when it is greater than or equal to 256, before the
mac_address_pool and hw_mac_address_ranges values format it with %02x. Preserve
the existing index calculation for valid indices and use the chart’s established
template failure mechanism.
- Around line 29-35: Update the macAddressPool and hwMacAddressRanges generation
toggle assignments, including $macPoolEnabled and $hwMacRangesEnabled, so
explicit false values are preserved instead of being replaced by default true.
Use dig with an enabled key default or an explicit key-presence check, while
retaining true as the fallback when the key is absent.