[codex] feat(tty): add command batching

[tonyfettes]

Summary

• Add destination-passing VT helpers so dynamic terminal sequences can be written into an existing buffer.
• Add root Command data values and Tty::execute to batch pure output commands into one serialized write.
• Cover command batching with pipe-backed root tests and record the design checkpoints under docs/plans/.

Notes

This first batch intentionally covers write-only commands. Terminal query commands, with_* scope helpers, and mouse composite commands are left out for a later design pass.

Validation

• moon fmt
• moon test internal/vt
• moon test .
• moon test
• moon check
• moon info
• git diff --cached --check

[chatgpt-codex-connector]

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