trust/skip TLS verification for MCP HTTP servers

Describe the feature or problem you'd like to solve

trust/skip TLS verification for MCP HTTP servers with invalid SAN certs (rustls hard-fails, no insecure option)

Proposed solution

Copilot CLI cannot connect to a remote HTTP MCP server whose TLS certificate has an invalid Subject Alternative Name (e.g., a literal  *  instead of a proper wildcard/IP SAN), even after the cert's issuing CA is explicitly trusted. There is no config option or environment variable to bypass hostname/certificate verification for a specific MCP server, which blocks use cases like connecting to on-prem/IoT devices with embedded mcp server and self-managed certificates addressed by IP Address.

Steps to reproduce

1. device that presents a self-signed certificate whose Subject/SAN is not a valid match for the IP address (e.g., CN/SAN =  * )
2. Export and trust the CA:  export NODE_EXTRA_CA_CERTS=~/ctrlx.pem 
3. Run  copilot , then  /mcp  — the server still fails to connect.

Requested behavior

The CLI offers a supported way to relax verification for a specific MCP server (e.g., a per-server  tls.insecureSkipVerify or honoring a documented env var), similar to how  curl -k  or Node's  NODE_TLS_REJECT_UNAUTHORIZED=0  work for other tools.

Example prompts or workflows

NA

Additional context

• Related: #4364 documents a similar underlying issue (rustls/rustls-platform-verifier being stricter than curl/Node/Chrome for enterprise MCP registry TLS), suggesting this is a broader gap in the Rust-based MCP networking layer, not specific to one code path.
• For comparison, Claude Code and Gemini CLI's MCP clients run on Node.js, so  NODE_TLS_REJECT_UNAUTHORIZED=0  works as an (insecure) escape hatch there; Copilot CLI has no equivalent because of the runtime split.
• Use case: connecting to on-prem/IoT devices reachable only via IP address with vendor-managed self-signed certificates that can't easily be reissued with a proper SAN.

Read related issue #4364, then trace the Rust-based MCP networking layer used when /mcp connects to an HTTP server. Reproduce the failure with the invalid-SAN certificate and determine where a per-server insecure option or documented environment variable would apply; done means the CLI can connect to that server through the supported configuration.