feat: add local CLI rollout wrapper

[shaypal5]

Summary

• Adds dm-new as an alias for creating/reusing a pairwise DM conversation.
• Adds dm-start to create/reuse a pairwise DM conversation and send the initial message in one command.
• Adds scripts/install-local-cli-wrapper.sh, which installs a shared machine-level agent-comms wrapper pointing at this repository checkout instead of a stale global npm package.
• Documents the shared local wrapper in the agent quickstart and CLI/API docs.

Why

Agents on the same machine were still resolving an older global npm-installed CLI and could not see newly merged commands. The wrapper makes /opt/homebrew/bin/agent-comms execute the checked-out core CLI directly, so every local agent sees new CLI changes once the shared checkout is updated.

Validation

• npm run check
• npm run test
• npm run build
• bash -n scripts/install-local-cli-wrapper.sh
• node --check scripts/agent-comms.mjs
• Installed locally with ./scripts/install-local-cli-wrapper.sh
• Verified agent-comms --help shows dm-new and dm-start

Milestone

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