feat(cli): add native HTTPS/TLS and URL scheme parsing support

[abn]

This PR adds native HTTPS/TLS negotiation and URL scheme parsing to the C++ CLI client (lemonade). This allows the CLI to seamlessly connect to secure remote endpoints (e.g., platforms like Modal, Cloudflare tunnels, or reverse proxies) equivalent to the desktop client.

Key Changes

• HTTPS/TLS Transport: Integrated OpenSSL (libssl/libcrypto) into the build pipeline and compiled the CLI target with CPPHTTPLIB_OPENSSL_SUPPORT enabled.
• URL Scheme Parser: Added a portable URL parser (ParseTargetUrl) to strip schemes (https://, http://), clean trailing paths/slashes, and automatically default missing ports (443 for HTTPS, 80 for HTTP) while respecting explicit port overrides.
• Client Integration: Updated the C++ CLI client constructor and command entry points to dynamically initialize secure or insecure transports, and enabled secure URL browser launching (open_url).
• Offline-safe Unit Tests: Added automated test coverage (CLIUrlSchemeTests in test/server_cli2.py) using a local mock HTTP server on an ephemeral port. This verifies HTTP/HTTPS routing and TLS handshake attempts deterministically without relying on external internet access.

Verification

• HTTPS Target: LEMONADE_HOST=https://httpbin.org lemonade list correctly defaults to port 443, resolves the domain, negotiates TLS, and completes the connection.
• HTTP Target: LEMONADE_HOST=http://httpbin.org lemonade list correctly routes to port 80.
• Local Fallback: lemonade list without a host successfully preserves the fallback to 127.0.0.1:13305.
• Automated Suite: PYTHONPATH=test python -m unittest server_cli2.CLIUrlSchemeTests -> PASS (2/2 tests).