Expose clipboard read and write

[thymikee]

There is no way to read or write the device clipboard from agent-device. This blocks testing:

• Copy/paste flows
• Share extensions and "Share to app" behavior
• OTP auto-fill (paste from clipboard)
• "Copy link" and similar features

These flows are extremely common in real apps.

Proposal: Add commands (or subcommands), e.g.:

• clipboard read — output current clipboard content (text) in session/JSON
• clipboard write <text> — set device clipboard to given text

Implementation: iOS can use simctl or runner automation to read/write pasteboard; Android can use adb shell am broadcast with clipboard provider or content/service. Prefer a single command family (clipboard read / clipboard write) for consistency.

Acceptance criteria:

• Read clipboard text from current device/session
• Write clipboard text on current device/session
• Supported on iOS simulator and Android emulator/device (document any limits)
• Docs and skill updated