⚡ Optimize quiz page N+1 query

[xRahul]

💡 What:

• Replaced the nested loop query for fetching answers with a single WHERE IN query (Eager Loading).
• Grouped answers by question_id in PHP.
• Replaced ORDER BY rand() for answers with PHP shuffle().
• Replaced rowCount() check on stmtCheck with fetch() to fix a reliability issue discovered during testing.

🎯 Why:

• The previous implementation executed N+1 queries (1 for questions + N for answers), which is inefficient and scales poorly.
• The optimization reduces database round-trips significantly.
• rowCount() on SELECT statements is not guaranteed to work on all PDO drivers (e.g. SQLite), causing issues in testing environments and potentially some production setups.

📊 Measured Improvement:

• Benchmark using SQLite memory DB showed ~30% improvement in raw execution time. In a real network environment with MySQL, the improvement would be significantly higher due to reduced network latency (N+1 round trips vs 2 round trips).

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PR created automatically by Jules for task 1378529226934035074 started by @xRahul

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