Cloud sessions: directory sync removed, legacy bundle upload retired on macOS and Linux

What

When you start a cloud session, for example with claude --cloud, Claude Code has to get your local files to it. Several ways of doing this were removed or narrowed:

• Directory sync is gone. These environment variables are no longer read anywhere: CLAUDE_CODE_DISABLE_DIR_SYNC, CLAUDE_CODE_DIR_SYNC_GIT, CLAUDE_CODE_DIR_SYNC_STREAM, CLAUDE_CODE_DIR_SYNC_ENGINE, CLAUDE_CODE_DIR_SYNC_FFWD and CLAUDE_CODE_DIR_SYNC_DISABLE_ANCHORING. The first-upload and folder-seeding steps are gone, along with the note that your folder is not a git repository and the hint to run CLAUDE_CODE_DIR_SYNC_ENGINE=none claude --cloud. Sessions now report directory sync as off.
• Uploading your repository as a git bundle (one file holding the repository) remains. The old message "Cannot start a cloud session from this folder right now" and the reroute and fallback paths after a bundle failure are gone.
• CLAUDE_CODE_LEGACY_BUNDLE is no longer honoured on macOS and Linux. Setting it there logs "CLAUDE_CODE_LEGACY_BUNDLE is not honoured on macOS and Linux: the default upload method runs". Only Windows keeps the older path. A new message suggests pushing your work and connecting GitHub instead. It was also dropped from a list of bundle variables that now holds only CCR_ENABLE_BUNDLE and CCR_FORCE_BUNDLE, though it is still used elsewhere.
• When a bundle upload fails with an unsupported layout, falling back to the older capture method now depends on a check. If the check says no, the upload is refused.
• Sessions tied to a device fail early if they are created with built-in tools and a first message together. The session request now also carries maxTurns and builtinTools.
• The waiting message is shorter: "A message is waiting · esc to take it back" instead of mentioning files still syncing.
• Interrupting or timing out while a cloud session is still being created now says so, for example "Interrupted while the cloud session was being created - it may still be running".

Why

If you relied on any CLAUDE_CODE_DIR_SYNC_* variable, or on CLAUDE_CODE_LEGACY_BUNDLE on a Mac or Linux machine, it no longer has any effect. Some cloud sessions that used to start by falling back to another method may now fail with a message, and connecting GitHub is the suggested way around it.