fix(web): add copying terminal selection with ctrl+c in the web app - #5638

💭 Looking at the diff, this is about terminal copy behavior and clipboard handling through context menus — none of the modified files like localApi.ts, contextMenuFallback.ts, surface.ts, or ipc.ts appear to involve Effect service code, so I should verify that quickly. I need to quickly check ipc.ts and ThreadTerminalDrawer.tsx to see if there's any Effect usage I'm missing. There's a tension between the customer's request for an exact "All clear" response and the schema requirement for valid JSON. I'll resolve this by putting "All clear" in the summary field while maintaining the JSON structure, treating it as a successful check with no findings.