Initial commit: Home automation docs and CODESYS project

- Reorganized project: codesys/, docs/codesys|redesign|integration|reference/, scripts/
- CODESYS project and exports in codesys/
- Documentation index in docs/README.md
- Redesign and light naming configuration
- Water boiler control and safety design

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/redesign/fb_switch-analysis-summary.md

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+# fb_switch Analysis Summary
+
+## Quick Assessment
+
+**Current Approach**: ⚠️ **Needs Improvement**
+
+**Main Issue**: Toggle-based control causes state desynchronization with Home Assistant.
+
+## Key Problems
+
+### 1. State Desynchronization
+- **Problem**: HA sends ON/OFF commands, but CODESYS toggles
+- **Result**: HA thinks light is ON, sends ON again → CODESYS toggles it OFF
+- **Impact**: Lights don't match HA state
+
+### 2. No Status Feedback
+- **Problem**: Status comes from toggle button, not actual relay
+- **Result**: Can't detect relay hardware failures
+- **Impact**: HA may show wrong status
+
+### 3. Mixed Control Sources
+- **Problem**: HA and Zigbee both use same toggle mechanism
+- **Result**: Conflicting behaviors
+- **Impact**: Unpredictable control
+
+## What You Need
+
+✅ **Control from Home Assistant** (ON/OFF switches)  
+✅ **Control from Zigbee switches** (toggle behavior)  
+✅ **Status feedback** (actual relay state)
+
+## Recommended Solution
+
+### Option 1: Full Redesign (Recommended)
+- Separate ON/OFF commands for HA
+- Edge detection for Zigbee (toggle)
+- Read actual relay status from EtherCAT
+- Clear priority system
+
+**Pros**: Clean, maintainable, extensible  
+**Cons**: Requires more changes
+
+### Option 2: Simplified Improvement
+- Add ON/OFF commands alongside toggle
+- Keep most existing structure
+- Add status feedback
+
+**Pros**: Less changes, faster to implement  
+**Cons**: Less clean, still some complexity
+
+## Quick Fix (Minimal Changes)
+
+If you need a quick fix while planning the redesign:
+
+1. **In Node-RED**: Convert HA ON/OFF to edge pulses
+   ```javascript
+   // Only send toggle on state change
+   if (currentState !== newState) {
+       sendToggle = true;
+   }
+   ```
+
+2. **Add status readback**: Read actual EtherCAT output state
+   ```iec
+   lights.l_1_status := EtherCAT_Output_Channel_1;
+   ```
+
+3. **Update HA**: Use state topic for status feedback
+
+## Decision Matrix
+
+| Approach | Complexity | Time | Maintainability | Recommended For |
+|----------|-----------|------|-----------------|-----------------|
+| Full Redesign | High | 2-3 days | Excellent | Long-term solution |
+| Simplified | Medium | 1 day | Good | Quick improvement |
+| Quick Fix | Low | 2-4 hours | Fair | Temporary solution |
+
+## My Recommendation
+
+**Start with Quick Fix** → **Then implement Simplified** → **Plan Full Redesign**
+
+This gives you:
+1. Immediate working solution
+2. Better solution in short term
+3. Best solution for long term
+
+---
+
+**See**: [Full Redesign Recommendation](fb_switch-redesign-recommendation.md) for detailed implementation.