Unify DevTools panels and add port discovery for remote inspectors

[DjDeveloperr]

Summary

• Merge Chrome/Metro and WebKit inspection into one right-side DevTools panel with a single target list, shared resize/popup controls, and no header
• Add discovery for common Metro and Chrome Inspector ports, with proxying through SimDeck so targets can be attached reliably
• Update the browser UI, API types, and docs to reflect the unified DevTools workflow

Testing

• cargo test --manifest-path server/Cargo.toml
• cargo clippy --manifest-path server/Cargo.toml --all-targets -- -D warnings
• npm run --prefix client test -- --run
• npm run lint
• npm run build
• Local browser smoke verified the unified panel renders, target switching works, and DevTools proxies connect end to end