Start a new project from a stack

Work in the main session. Do not start other agents for this.

1. Call stack_list, and stack_show for the likely candidates. Recommend one stack in a sentence and say why; ask the owner for the project name if they have not given it.
2. Call bootstrap with the stack and name. It refuses a directory that exists and is not empty; if it does, report that and stop.
3. Call gate on the new project straight away, before anything is added, to prove the scaffold builds. Report the result exactly as it came back.
4. Record a journal_add of kind status for the new project: the stack, the gate result and its machine, and what the owner said the project is for. Ask for a one-line summary if there is none, and tell the owner the summary line to put in its registry file.