When git push or other git operations hang waiting for credential/browser
auth, show a helpful message to the user after 5 seconds of inactivity
instead of appearing frozen.
Added:
- runCmdWithTimeoutMessage() in internal/syncbranch/worktree.go
- runGitCmdWithTimeoutMsg() in cmd/bd/sync.go
- Both functions print a message after timeout delay with advice
to check for browser auth prompts
Fixes issue #647 (bd sync frozen waiting for browser auth)