[FEAT] Add support for mTLS to loki backend

[dewjam]

Add mTLS Authentication

Changes

• Added mTLS support via LOKI_CLIENT_CERT, LOKI_CLIENT_KEY, LOKI_CA_CERT environment variables
• Added TLS skip verification via LOKI_TLS_INSECURE_SKIP_VERIFY for development
• Implemented proper CA certificate loading and validation
• Applied TLS configuration to all three Loki tools

Security

• All TLS settings are environment-only, not LLM-overridable
• Certificate paths locked at deployment level

[CLAassistant]

All committers have signed the CLA.