Add client-side JS/TS code execution

[dreamteam-mobile]

Summary

• Run JS/TS code in-browser via Web Workers — sandboxed execution with console interception, 10s timeout, and 100KB output cap
• Run/Stop button in the tab bar (green play / red stop) with Ctrl/Cmd + Enter keyboard shortcut
• Collapsible output panel below the editor with color-coded stdout/stderr, execution duration, and auto-scroll
• Execution results sync to all participants over the existing WebRTC DataChannel
• Executable languages marked with ▶ icon in the language selector dropdown
• Responsive layout for desktop, tablet, and mobile viewports

Implementation

Component	Description
code-executor.worker.ts	Web Worker with new Function() sandbox, console interception, TypeScript transpilation via transpileModule()
code-executor.ts	Service layer managing Worker lifecycle (spawn/terminate/timeout)
executionStore.ts	Zustand store for execution state (isRunning, output, panelExpanded)
useExecutionSync.ts	Sync hook broadcasting execution-start / execution-result over DataChannel
OutputPanel.tsx	Collapsible output panel with status indicators and color-coded output

Screenshot

JavaScript fibonacci function executed with output panel showing results

Test plan

• All 1214 unit tests pass
• TypeScript typecheck passes
• Write JS code → Ctrl+Enter → output appears in panel
• Write TS code with type annotations → Run → transpilation + output works
• Test while(true){} → 10s timeout triggers, stop button works
• Test console.error() → red text in output panel
• Select non-executable language → Run button hidden, output panel hidden
• Two peers connected → execution results sync via WebRTC
• Mobile viewport → output panel responsive, buttons right-aligned