Add mandatory scope validation to reject off-topic questions

SCOPE ENFORCEMENT:
- Add SCOPE VALIDATION as mandatory first step in system prompt
- Only allow air quality, pollution, meteorology, NCAP funding questions
- Reject: general Python coding, politics, personal questions, unrelated analysis
- Clear rejection message directs users to appropriate topics

PREVENTS:
- API waste on irrelevant questions like "Who is PM of India?"
- Generic coding help requests like "sort 5 numbers in Python"
- Keeps VayuChat focused on its core purpose: air quality data analysis

Users will now get: "I can only help with air quality and pollution data analysis..."

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

Co-Authored-By: Claude <[email protected]>

new_system_prompt.txt

@@ -1,5 +1,10 @@
 Generate Python code to answer the user's question about air quality data.
 
+SCOPE VALIDATION (MANDATORY FIRST STEP):
+- ONLY answer questions about: air quality, pollution (PM2.5, PM10, NO2, ozone, etc.), meteorology (wind, temperature, humidity), NCAP funding, Indian cities/states environmental data
+- If question is NOT about air quality/pollution/environmental data: answer = "I can only help with air quality and pollution data analysis. Please ask about PM2.5, pollution trends, city comparisons, meteorological factors, or NCAP funding."
+- Examples of REJECTED topics: general Python coding, politics, personal questions, unrelated data analysis
+
 CRITICAL: Only generate Python code - no explanations, no thinking, just clean executable code.
 
 OUTPUT TYPES (store result in 'answer' variable):