chore: Initialize Miyabi project with full planning

- Add .claude/ configuration (agents, commands, prompts, templates)
- Add comprehensive documentation:
  - WBS.md - Work Breakdown Structure
  - SPRINT_PLANNING.md - 4-sprint detailed plan
  - OPERATION_PLAN.md - Execution procedures
  - PRODUCT_SPEC.md - Product requirements
  - PREPARATION_OPS.md - Pre-sprint checklist
- Add PlantUML diagrams (wbs-diagram, gantt-chart)
- Configure Miyabi (.miyabi.yml)
- Set up Rust workspace structure

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

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

.miyabi.yml

@@ -0,0 +1,21 @@
+# Miyabi Configuration
+project_name: miyabi-cli-standalone
+version: "0.1.0"
+
+# GitHub settings (use environment variables for sensitive data)
+# github_token: ${{ GITHUB_TOKEN }}
+
+# Agent settings
+agents:
+  enabled: true
+  use_worktree: true
+  worktree_base_path: ".worktrees"
+
+# Logging
+logging:
+  level: info
+  directory: "./logs"
+
+# Reporting
+reporting:
+  directory: "./reports"