feat(editor): Enable copying request details

[lucasAguiar11]

What & why

Enables native text selection and copying in the Inspect request modal, the Sent request summary, and Timing event rows.

The implementation reuses the existing .selectable-text convention. It adds no Clipboard API, state, IPC, dependencies, or shortcuts. Timing row prefixes are now included in selections while filters, virtualization, linked-request navigation, and masked secrets remain unchanged.

Verification

• bun run typecheck
• bun run lint
• bun run test — 203 passed, 0 failed
• bun run build
• Tauri visual smoke test

Checklist

• bun run typecheck, bun run lint, and the cargo checks pass (see CONTRIBUTING.md)
• New Tauri commands are registered in collect_commands! and bun run codegen was run — not applicable; no Tauri command changed
• Follows the rules in AGENTS.md (file-size limits, render-loop rules, no migration shims)