Update gcal design with implementation progress

Mark skill, command, and helper as complete.
OAuth setup and testing remain.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plans/2025-01-02-gcal-design.md

@@ -221,9 +221,9 @@ Calendar scope not authorized. Run:
 ## Implementation Checklist
 
 - [ ] Add Calendar scope to GCP OAuth app
-- [ ] Create `~/.claude/skills/gcal/SKILL.md`
-- [ ] Create `~/.claude/commands/gcal.md`
-- [ ] Create `~/.claude/mcp/delegation/gcal_delegate.py`
+- [x] Create `~/.claude/skills/gcal/SKILL.md`
+- [x] Create `~/.claude/commands/gcal.md`
+- [x] Create `~/.claude/mcp/delegation/gcal_delegate.py`
 - [ ] Test OAuth re-authorization
 - [ ] Test all subcommands
 - [ ] Test natural language fallback