Clearer file sync messages for conflicts, restricted connections and empty starts

Cloud file sync, which copies your working folder to a cloud session, now handles several edge cases differently:

• Unresolved git conflicts when a session is created: the message now says the conflicted files did not go up and will go with your first message once you resolve the conflicts or abort the merge, rebase, cherry-pick, revert or stash pop. Before, this used generic wording.
• A connection lost for compliance reasons: Claude Code no longer re-announces the folder or retries the first upload.
• The install acknowledgement is now skipped while an upload has been announced.
• A file that cannot be read because of where its attributes come from now gets its own suggested fix.
• A checkout started empty, when a synced session is not offered: the message now explains that a synced session would have to start from one upload of the checkout's history and files.