feat: cac env import — migrate from bare Claude Code

[nmhjklnm]

Summary

Users who already use bare Claude Code have sessions, memory, credentials in ~/.claude/. After installing cac, they need a way to migrate their existing state into a cac environment.

Proposed API

cac env import <name> [--from ~/.claude]    # default: import from ~/.claude

What to migrate

Source	Destination	Action
~/.claude/ (sessions, settings.json, CLAUDE.md, projects/)	~/.cac/envs/<name>/.claude/	Copy
~/.credentials.json	~/.cac/envs/<name>/.claude/.credentials.json	Copy
.claude.json userID/anonymousId	—	Regenerate (isolated identity)
statsig	—	Regenerate
Telemetry cache (numStartups, etc.)	—	Do NOT migrate

What to generate fresh

• uuid, stable_id, user_id, machine_id, hostname, mac_address
• mTLS client certificate

Reverse operation

cac env export <name> [--to ~/backup/]      # export environment snapshot

Implementation notes

• Add to src/cmd_env.sh as _env_cmd_import
• Similar flow to _env_cmd_create but copies existing .claude/ instead of creating empty

[nmhjklnm]

Closing as no longer planned.