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/esp32_basics.py

@@ -0,0 +1,37 @@
+import re
+from . import BaseValidator
+
+class ESP32Validator(BaseValidator):
+    def validate(self, code: str, hardware: str, user_message: str) -> list[dict]:
+        issues = []
+        if "ESP32" in hardware.upper():
+            # Check 1: analogWrite
+            if "analogWrite" in code:
+                issues.append({
+                    "severity": "error",
+                    "line": self.find_line(code, "analogWrite"),
+                    "message": "ESP32 doesn't support analogWrite(). Use ledcWrite()",
+                    "fix": lambda c: c.replace("analogWrite", "ledcWrite")
+                })
+            
+            # Check 18: ADC Resolution
+            adc_res_match = re.search(r'#define\s+(\w*ADC\w*RES\w*)\s+(\d+)', code, re.IGNORECASE)
+            if adc_res_match:
+                val = int(adc_res_match.group(2))
+                if val not in [4095, 4096]:
+                     issues.append({
+                        "severity": "error",
+                        "line": self.find_line(code, adc_res_match.group(0)),
+                        "message": f"Hardware Mismatch: ESP32 ADC is 12-bit (4095), not {val}.",
+                        "fix": lambda c, old=adc_res_match.group(0), name=adc_res_match.group(1): c.replace(old, f"#define {name} 4095")
+                    })
+            
+            # Check 20: Hardcoded 10-bit ADC math
+            for match in re.finditer(r'/\s*(1023(?:\.0?)?f?|1024(?:\.0)f?)', code):
+                issues.append({
+                    "severity": "error",
+                    "line": self.find_line(code, match.group(0)),
+                    "message": "Hardware Mismatch: ESP32 ADC is 12-bit. Use 4095.0, not 1023/1024.",
+                    "fix": lambda c, m=match.group(0): c.replace(m, "/ 4095.0")
+                })
+        return issues