Add --insecure flag to skip TLS certificate validation

[mattt]

Related to #60

[Copilot]

Pull Request Overview

This PR adds an --insecure flag to skip TLS certificate validation, allowing connections to servers with invalid or self-signed certificates. The implementation involves refactoring the HTTP client configuration to use a structured options approach.

• Refactored RetryableClient function to accept a structured RetryableClientOptions parameter instead of individual parameters
• Added TLS certificate verification bypass functionality when the insecure flag is enabled
• Updated the CLI to include the new --insecure flag and pass it through to both HTTP clients

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
internal/http.go	Refactored client creation to use options struct and added insecure TLS configuration
cmd/emcee/main.go	Added insecure flag to CLI and updated client instantiation to pass insecure option

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