Add unit tests for analytics, fallback client, and refactored validators

- Implemented comprehensive unit tests for the BuddAI Analytics module, covering fallback statistics calculations.
- Created tests for the FallbackClient to ensure proper escalation to various AI models and handling of missing API keys.
- Developed unit tests for the refactored validator system, validating various hardware and coding standards.
- Established a base validator interface and implemented specific validators for ESP32, Arduino, motor control, memory safety, and more.
- Enhanced the validator registry to auto-discover and manage validators effectively.
- Included detailed validation logic for common issues in embedded systems programming, such as unused variables, safety timeouts, and coding style violations.

validators/registry.py

@@ -0,0 +1,63 @@
+"""
+Validator Registry
+Auto-discovers and manages validators
+"""
+
+import os
+import importlib
+from pathlib import Path
+from typing import List
+from .base_validator import BaseValidator
+
+class ValidatorRegistry:
+    def __init__(self):
+        self.validators = {}
+        self.load_validators()
+    
+    def load_validators(self):
+        """Auto-discover validators in validators/ folder"""
+        validator_dir = Path(__file__).parent
+        
+        for file in validator_dir.glob('*.py'):
+            if file.name.startswith('_') or file.name == 'base_validator.py':
+                continue
+            
+            # Import the module
+            module_name = file.stem
+            module = importlib.import_module(f'.{module_name}', package='validators')
+            
+            # Find validator classes
+            for attr_name in dir(module):
+                attr = getattr(module, attr_name)
+                if (isinstance(attr, type) and 
+                    issubclass(attr, BaseValidator) and 
+                    attr != BaseValidator):
+                    
+                    # Instantiate and register
+                    validator = attr()
+                    self.validators[validator.name] = validator
+                    print(f"✅ Loaded validator: {validator.name}")
+    
+    def get_validators_for(self, code: str, context: dict) -> List[BaseValidator]:
+        """Get validators that match this code/context"""
+        relevant = []
+        
+        for validator in self.validators.values():
+            if validator.matches_context(code, context):
+                relevant.append(validator)
+        
+        # Sort by priority (lower number = higher priority)
+        relevant.sort(key=lambda v: v.priority)
+        
+        return relevant
+    
+    def validate_all(self, code: str, context: dict) -> list:
+        """Run all relevant validators"""
+        validators = self.get_validators_for(code, context)
+        all_issues = []
+        
+        for validator in validators:
+            issues = validator.validate(code, context)
+            all_issues.extend(issues)
+        
+        return all_issues