Closes the new-project story (T-486). The dead-end "not a git repo" dialog now offers to initialize the folder: project.init runs git init + a non-clobbering scaffold, then opens + announces on projectCreatedChannel so the account roadblock fires — the same path a brand-new project takes. Adds initExistingProject + the `clide project init [--dir]` verb (default: the current workspace). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>