refactor(canvas): retire the OpenPencil daemon code

Merged
GN
2d ago
+596-3920

Summary

  • The OpenPencil sidecar never shipped and is replaced by the figcraft editor.
  • Part 8 of 10 in a stacked series. Review and merge bottom-up; each PR targets the one below it. Canvas mode v3 (figcraft engine). Spec: spec-openpencil-canvas-mode; architecture spine 2026-10-16 (AD-17 to AD-31).

Related Issue

No issue. Split from #1369 so each part stays under 50 files.

Type of Change

  • feat: new feature

What Changed

  • Deletes the daemon pool, handshake, relays and their tests; renames the token store.
  • Fixes reopening a canvas under \\?\ project roots on Windows desktop, and test setups the canvas work broke.
  • Adds docs/canvas.md.

Scope

  • E4-1 plus fixes found in desktop testing.

How It Was Tested

  • bun run typecheck on this branch
  • Each part is a checkpoint that was built and tested when it was made (cargo test for canvas and host_mcp, vitest, real runs in headless Edge). The bottom and top of the stack were rebuilt and re-tested on current dev.

Checklist

  • PR title follows the conventional commit format
  • Explained why no issue exists
  • Added or updated tests
  • Read AGENTS.md
  • A human reviewed the complete diff before submission

🤖 Generated with Claude Code

Summary by cubic

Removes the never-shipped OpenPencil daemon backend and replaces it with the figcraft editor, and fixes reopening a canvas when the project root is a verbatim Windows path.

  • Deletes the daemon pool, spawner, handshake, HTTP proxy, and the root /pkg, /canvaskit, and /api relays.
  • Removes the canvas_save, canvas_status, and canvas_bundle_base commands and routes; they had no callers.
  • Renames the canvas session cookie from op_canvas_ct_<id> to canvas_ct_<id>.
  • Fixes canvas reopen failures on Windows where the project registry stores \\?\D:\... roots: client paths are normalized to plain backslash form before validation.
  • Renames .op and .pen document references to .figcraft throughout the renderer, tests, and docs.
  • Adds docs/canvas.md describing the figcraft canvas design, lifecycle, and security.