Add local-first Secret Detector for configs and infrastructure files

[shadowbipnode]

Add a local-first secret detection tool for infrastructure and configuration files.

Goals:

• detect hardcoded secrets
• detect exposed API tokens
• detect private keys
• detect plaintext credentials
• entropy-based secret heuristics
• offline/local-first analysis

Supported inputs:

• .env files
• docker-compose
• Terraform
• shell scripts
• nginx configs
• Kubernetes manifests

Output should include:

• severity scoring
• detected secret type
• remediation guidance
• safer alternatives
• verification recommendations

The tool should work fully offline and integrate with SysAI operational trust semantics.