docs: Add implementation status section to DESIGN.md

Added clear implementation status tracking to DESIGN.md to show what's
currently working vs. what's planned.

Changes:
- Updated document version to v2.1
- Added "Implementation Status (2025-11-01)" section at top
- Created DESIGN.md.old backup for easy comparison
- Categorized features into: Implemented, In Progress, Planned

Current Status:
✅ Implemented: Stages 1-2, cascading rules, AI patch generation, voting
🚧 In Progress: Stage 3 (Design Discussion Gate) - being implemented now
📋 Planned: Stages 4-7, moderator protocol, bug sub-cycles

The three-stage workflow (Feature → Design → Implementation) was always
documented correctly in DESIGN.md. The current implementation just skips
the Design stage, which we're now fixing.

This status section will be updated as each milestone is completed.

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

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

docs/DESIGN.md

@@ -1,11 +1,38 @@
 # CascadingDev - AI–Human Collaboration System
-## Process & Architecture Design Document (v2.0)
+## Process & Architecture Design Document (v2.1)
 - Feature ID: FR_2025-10-21_initial-feature-request
 - Status: Design Approved (Ready for Implementation)
-- Date: 2025-10-21
+- Date: 2025-10-21 (Updated: 2025-11-01)
 - Owners: Rob (maintainer), AI_Moderator (process steward)
 - Contributors: AI_Claude, AI_Deepseek, AI_Junie, AI_Chat-GPT, AI_GitHubCopilot
 
+## Implementation Status (2025-11-01)
+
+### ✅ Currently Implemented (Milestone M0-M1)
+- **Stage 1: Request** - Feature request creation and automation
+- **Stage 2: Feature Discussion** - Discussion file generation, voting, summaries
+- **Cascading Rules System** - .ai-rules.yml loading and merging
+- **AI Patch Generation** - Claude API integration, diff application
+- **Vote Tracking** - VOTE: line parsing, summary updates
+- **Pre-commit Hook** - Automation orchestration, file staging
+- **Setup Script** - Project initialization with Ramble GUI
+
+### 🚧 In Progress (Current Focus)
+- **Stage 3: Design Discussion Gate** - Currently skipped, being implemented
+  - Will create design.discussion.md when feature status = READY_FOR_DESIGN
+  - Will maintain design/design.md document
+  - Requires design_gate_writer and design_discussion_writer rules
+
+### 📋 Planned (Milestones M2-M4)
+- **Stage 4: Implementation Discussion** - Task tracking, human approval gates
+- **Stage 5: Testing Discussion** - Test planning, bug sub-cycles
+- **Stage 6: Review Discussion** - Final review, release promotion
+- **Stage 7: Release** - Changelog generation, version tagging
+- **Moderator Protocol** - Nudge system, escalation paths
+- **Bug Sub-Cycles** - Integrated bug tracking within features
+
+---
+
 ## Table of Contents
 - Executive Summary
 - Repository Layout