Initialize new project types

[ktaletsk]

Summary

• Adds a "Create Project" dialog that lets users initialize new project types directly from JupyterLab
• Backend: new GET /creatable-types (cached) and POST /create endpoints that introspect the projspec registry and call Project.create()
• Frontend: searchable/filterable type picker dialog with colored badges and descriptions, launched via:
  • "+" button in the sidebar header
  • Command palette ("Initialize Project Type")
  • Right-click context menu on directories in the file browser
• Already-detected project types are excluded from the list
• Success triggers a sidebar/chips re-scan and a toast notification
• Bumps version to 0.3.0 and requires projspec >0.2.0 for the updated Project.create() API

Files changed

Area	Files
Backend	jupyter_projspec/routes.py — new CreatableTypesRouteHandler, CreateRouteHandler, caching logic
Types & API	src/types.ts, src/api.ts — new interfaces and fetchCreatableTypes(), createProject() wrappers
Dialog	src/components/CreateProjectDialog.tsx — new searchable type picker component
Sidebar	src/components/ProjspecPanelComponent.tsx, src/widgets/ProjspecPanel.ts — "+" button, refreshScan()
Wiring	src/index.ts — command registration, palette, context menu, post-create refresh + notification
Chips	src/widgets/ProjspecChipsWidget.ts — refreshScan() for post-create update
Styles	style/base.css — create button and dialog styling
Config	package.json, pyproject.toml — version bump to 0.3.0, projspec >0.2.0

Dependencies

Requires an unreleased version of projspec (>0.2.0) for Project.create() -> list[str]. See fsspec/projspec#73 for the release request.

[github-actions]

👈 Launch a Binder on branch fsspec/jupyter-projspec/feature%2Finitialize-new-project

[martindurant]

0.3.0 is out