feat: Add debug mode to inspect LLM prompts and responses

- Add DebugContext to track all LLM interactions
- Create DebugPanel component with floating UI
- Track prompts/responses in Tutor component (move analysis, hints, questions)
- Track prompts/responses in Analysis page (move commentary)
- Add NEXT_PUBLIC_DEBUG environment variable to enable/disable
- Include metadata (FEN, personality, language, etc.) in debug entries
- Add copy-to-clipboard and clear functionality
- Add DEBUG_MODE.md documentation

src/contexts/DebugContext.tsx

@@ -0,0 +1,59 @@
+"use client";
+
+import React, { createContext, useContext, useState, ReactNode } from 'react';
+
+export interface DebugEntry {
+    id: string;
+    timestamp: number;
+    type: 'tutor' | 'analysis';
+    action: string; // e.g., "Best Move", "Hint", "General Question", "Move Analysis"
+    prompt: string;
+    response?: string;
+    metadata?: Record<string, any>;
+}
+
+interface DebugContextType {
+    isDebugMode: boolean;
+    entries: DebugEntry[];
+    addEntry: (entry: Omit<DebugEntry, 'id' | 'timestamp'>) => void;
+    clearEntries: () => void;
+}
+
+const DebugContext = createContext<DebugContextType | undefined>(undefined);
+
+export function DebugProvider({ children }: { children: ReactNode }) {
+    // Check if debug mode is enabled via environment variable
+    const isDebugMode = process.env.NEXT_PUBLIC_DEBUG === 'true';
+    const [entries, setEntries] = useState<DebugEntry[]>([]);
+
+    const addEntry = (entry: Omit<DebugEntry, 'id' | 'timestamp'>) => {
+        if (!isDebugMode) return; // Don't track if debug mode is off
+        
+        const newEntry: DebugEntry = {
+            ...entry,
+            id: `${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
+            timestamp: Date.now(),
+        };
+        
+        setEntries(prev => [...prev, newEntry]);
+    };
+
+    const clearEntries = () => {
+        setEntries([]);
+    };
+
+    return (
+        <DebugContext.Provider value={{ isDebugMode, entries, addEntry, clearEntries }}>
+            {children}
+        </DebugContext.Provider>
+    );
+}
+
+export function useDebug() {
+    const context = useContext(DebugContext);
+    if (context === undefined) {
+        throw new Error('useDebug must be used within a DebugProvider');
+    }
+    return context;
+}
+