docs(sca): document private registry access via network broker

[salolivares]

Context

Supply Chain recently added a Use network broker for registry access
checkbox when connecting a private registry, letting Semgrep reach registries
that are only accessible from a customer's private network. The docs didn't
cover this option, and the existing Registry support section incorrectly
stated private registries weren't supported.

Solution

• Correct the Registry support section: public npm/PyPI and private PyPI
  registries are supported, with a link to the connect flow.
• Add an optional step to the Connect a private registry flow documenting
  the Use network broker for registry access checkbox, calling out that it
  requires a deployed Network Broker and that the broker allowlist must
  include the registry URL.
• Add a Use Semgrep Network Broker for private registry access section to
  the Network Broker page with the required allowlist config (GET/HEAD
  on the registry host). Cross-linked both directions.

Testing plan

• Verified internal links resolve to real anchors (#registry-support,
  #connect-a-private-registry-to-semgrep,
  #use-semgrep-network-broker-for-private-registry-access).
• Visual check of the nested list and tooltip rendering in local preview.

[mintlify]

Preview deployment for your docs. Learn more about Mintlify Previews.

Project	Status	Preview	Updated (UTC)
semgrep-docs	🟢 Ready	View Preview	Jun 1, 2026, 10:09 PM

[abhijna]

Lgtm! This triage and remediation doc is getting long and could probably use some reorg and trimming. We can do this in a separate PR.