Adds project-scoped planning directory resolution via GSD_PROJECT
environment variable. When set, planningDir() routes to
.planning/{project}/ instead of .planning/, enabling multiple
independent projects to coexist under a single .planning/ root.
Use case: shared workspaces (e.g., Obsidian vaults, monorepo knowledge
bases) where multiple projects are managed from one directory. Each
project keeps its own config.json, ROADMAP.md, STATE.md, and phases/
under .planning/{project-name}/.
GSD_PROJECT follows the same pattern as GSD_WORKSTREAM and can be
combined with it: .planning/{project}/workstreams/{ws}/
Also updates loadConfig() to read config.json from the project-scoped
directory when GSD_PROJECT is active.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
3b0a7560e5