Adds .devfoundry/skills/new-project-reset.md: a one-time, explicitly-triggered
procedure for clearing DevFoundry's own internal process-development history
(specs/archive/, specs/active/, specs/.spec-counter, improvement-log.md
entries, and any residual project-specific facts in .devfoundry/references/)
when this template is copied to start a real project. It never runs
automatically or as part of the normal per-spec Archive step (AGENTS.md
Collaboration Rule 6 makes that explicit).

The skill was authored but deliberately not run against this repo - the
archive still holds SPEC-001 through SPEC-006 intact.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>