Native support for continuing a session across machines

Summary

Sessions can't be continued on a different machine today. The transcript, memory, and plan files all live on-disk under ~/.claude/projects/<project-hash>/, but the hash is derived from the absolute cwd, so even syncing ~/.claude/ via iCloud doesn't reliably carry a session across machines unless both repos happen to live at identical paths.

Current workaround

Manually zip and transfer:

• ~/.claude/projects/<project-hash>/ (session transcripts)
• ~/.claude/projects/<project-hash>/memory/ (persistent memory)
• ~/.claude/plans/*.md (plan files)

then claude --resume on the target machine. Works, but clunky and path-fragile.

Proposed

Account-bound sync for session transcripts + memory + plans. Concretely:

• claude session push to upload current session state
• claude --resume --from-cloud to show sessions from any of this user's machines

The surface is small — everything is already flat files (JSONL + markdown). Auth and account identity already exist in the CLI. The project-hash scheme could be replaced or supplemented with a project identifier resolved from git remote origin URL, so sessions re-associate across differing local paths.

Why it matters

Long sessions accumulate real context: plan files, feedback memory, project understanding. Rebuilding that after switching machines throws away value. Anyone with a laptop + workstation hits this.