Align WebSocket JSON color policy with HTTP auto mode

[ryanfowler]

Summary

• Use the shared core::color_enabled policy for non-interactive WebSocket JSON formatting so default terminal behavior matches HTTP output.
• Thread JSON color state into interactive WebSocket mode and preserve ANSI-aware wrapping so colored JSON renders correctly in the terminal UI.
• Add coverage for the WebSocket color policy and interactive JSON formatting paths.

Testing

• cargo fmt
• cargo clippy --locked --all-targets --all-features -- -D warnings
• cargo test --all-features