Refactor to unified firmware architecture with modular configuration system

BREAKING CHANGE: Replace separate anchor/tag firmware with single configurable codebase

## Major Changes
- **Unified Firmware**: Single main.cpp replaces main_anchor.cpp and main_tag.cpp
- **Modular Config**: Organized configuration system in src/config/ directory
- **Dynamic Behavior**: Device behavior determined by build flags at compile time
- **Simplified Builds**: Reduced from 8+ environments to 3 core environments

## New Architecture
- src/main.cpp - Single firmware with config-driven behavior
- src/config/device_config.h - Device role detection and unified behavior
- src/config/anchor_config.h - Anchor-specific settings (positioning, communication)
- src/config/tag_config.h - Tag-specific settings (USB streaming, coordinate collection)
- src/config/positioning_config.h - Distributed positioning algorithm framework

## Build System Improvements
- Simplified platformio.ini (anchor/tag/debug environments)
- Support for custom device ID and network via PLATFORMIO_BUILD_FLAGS
- Same firmware for all devices, behavior configured at compile time
- Easy device configuration: set PLATFORMIO_BUILD_FLAGS=-DUWB_INDEX=5 -DNETWORK_ID=2000

## Technical Benefits
- Reduced code duplication from ~350 lines to unified ~200 lines
- Consistent behavior across device types
- Easier maintenance with single codebase
- Framework ready for distributed positioning algorithm implementation
- Modular configuration system for future algorithm expansion

## Positioning Framework Ready
- Anchor discovery protocol framework established
- Inter-anchor communication configuration ready
- Position calculation algorithm structure in place
- Coordinate storage and validation system configured
- Tag coordinate collection and USB streaming framework prepared

## Testing
- ✅ Anchor build successful (325KB flash usage)
- ✅ Tag build successful (325KB flash usage)
- ✅ Custom device ID/network configuration working
- ✅ UWB initialization sequence fixed for active networks

CLAUDE.md

@@ -8,14 +8,20 @@ This is an ESP32-S3 based Ultra-Wideband (UWB) indoor positioning system for war
 
 **Key Architecture**: Battery-powered anchors auto-position themselves, mobile tag collects positioning data via USB to PC for real-time display and dual-file logging for offline analysis.
 
+**Unified Firmware**: Single codebase with config-driven behavior for all device types, organized in modular configuration structure.
+
 ## Development Commands
 
-### Build & Flash
+### Build & Flash (Unified Firmware)
 ```bash
-# Build specific device type
-pio run -e anchor      # Build anchor firmware
-pio run -e tag         # Build tag firmware  
-pio run -e tag2        # Build second tag (ID 2)
+# Build default configurations
+pio run -e anchor      # Build anchor (ID=0, Network=1234)
+pio run -e tag         # Build tag (ID=1, Network=1234)
+pio run -e debug       # Build debug anchor (ID=0, Network=1234)
+
+# Build with custom device ID and network
+set PLATFORMIO_BUILD_FLAGS=-DUWB_INDEX=5 -DNETWORK_ID=2000
+pio run -e anchor      # Build anchor ID=5, Network=2000
 
 # Flash to device
 pio run -e tag -t upload
@@ -26,10 +32,16 @@ pio device monitor
 ```
 
 ### Development Environments
-- **anchor**: Base station (UWB_INDEX=0, tracks tags)
-- **tag**: Mobile tracker (UWB_INDEX=1, reports to anchors)
-- **tag2**: Second mobile tracker (UWB_INDEX=2)
-- **debug**: Development build with DEBUG_ENABLED=1
+- **anchor**: Base station with distributed positioning (default: ID=0, Network=1234)
+- **tag**: Mobile tracker with coordinate collection (default: ID=1, Network=1234)  
+- **debug**: Development anchor build with DEBUG_ENABLED=1
+
+### Unified Architecture
+All devices now use the same `main.cpp` with config-driven behavior:
+- Device type determined by build flags (`DEVICE_TYPE_ANCHOR`/`DEVICE_TYPE_TAG`)
+- Behavior configured via `anchor_config.h` and `tag_config.h`
+- Positioning algorithm settings in `positioning_config.h`
+- Easy customization via `PLATFORMIO_BUILD_FLAGS` environment variable
 
 ## Core Architecture
 
@@ -41,10 +53,11 @@ Tags: Range to anchors <20> Collect coordinates <20> USB to PC <20> Real-time + log
 
 ### Key Technical Patterns
 
-**1. Dual Firmware Architecture**
-- `main_anchor.cpp`: Tracks tags, manages UWB_TAG_COUNT devices, displays active tags
-- `main_tag.cpp`: Connects to MAX_ANCHORS, reports to PC via USB, displays anchor distances
-- Shared: config.h for hardware pins, UWBHelper library for AT commands
+**1. Unified Firmware Architecture**
+- `src/main.cpp`: Single firmware for all devices, behavior determined by build flags
+- `src/config/`: Modular configuration system with device-specific settings
+- Dynamic behavior: Device type, peer management, and display logic configured at compile time
+- Shared: UWBHelper library for AT commands, unified communication and display handling
 
 **2. UWBHelper Library Structure**
 - **Complete AT Command Implementation**: All 21 commands from AT manual
@@ -75,6 +88,13 @@ Tags: Range to anchors <20> Collect coordinates <20> USB to PC <20> Real-time + log
 
 **Timeout Management**: Devices marked inactive after DEVICE_TIMEOUT (5000ms) with no updates
 
+**4. Modular Configuration System**
+- `src/config/config.h`: Hardware pin definitions and basic system settings
+- `src/config/device_config.h`: Device role detection and unified behavior configuration
+- `src/config/anchor_config.h`: Anchor-specific settings (tag tracking, positioning, inter-anchor communication)
+- `src/config/tag_config.h`: Tag-specific settings (anchor tracking, USB streaming, coordinate collection)
+- `src/config/positioning_config.h`: Distributed positioning algorithm parameters and validation settings
+
 ## Configuration Constants
 
 Key values in config.h:
@@ -87,11 +107,18 @@ Key values in config.h:
 ## Development Roadmap Context
 
 This ESP32 firmware implements the hardware foundation for the UWB positioning system (see docs/ROADMAP.md):
-- **Current**: Basic anchor-tag ranging with USB data streaming via UWBHelper library
-- **Next**: Anchor auto-positioning, coordinate relay through tag, battery optimization
+- **Current**: Unified firmware architecture with config-driven behavior, ready for distributed positioning implementation
+- **Framework**: Configuration structure established for anchor discovery, position calculation, coordinate storage, and data relay
+- **Next**: Implement anchor auto-positioning algorithms, coordinate relay through tag, battery optimization
 - **Goal**: <15min anchor setup, <30cm ranging accuracy, reliable USB data streaming to webapp
 - **WebApp Integration**: All data logging, visualization, and analysis handled by separate Next.js webapp
 
+### Distributed Positioning Framework Ready
+- **Anchor Behavior**: Framework for inter-anchor communication, discovery protocol, position calculation
+- **Tag Behavior**: Framework for coordinate collection, USB data streaming, real-time positioning
+- **Algorithm Foundation**: Trilateration, consensus mechanisms, coordinate system establishment
+- **Storage System**: EEPROM-based position persistence for battery-powered anchors
+
 ## Hardware Requirements
 
 - **Modules**: Makerfabs MaUWB ESP32-S3 with built-in UWB + OLED