feat: support multi-platform DSA problems and code optimization display

[TruCoded]

Feature Request: Multi-Platform Coding Problems & Code Optimization Output

Context & Scope

• Maintainer / Repository Owner: @TruCoded
• Difficulty: 🟡 Medium (Updates existing parsing tags, mock data, and UI dropdown logic)

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📖 Description

We want to expand our AI analysis feature to support multi-platform coding recommendations instead of restricting links strictly to LeetCode. Additionally, the backend and frontend need updates to extract, pass, and render the best-optimized version of the user's code along with its time and space complexities.

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Backend Implementation Tasks

ai_service.py

• Rename Tags: Change LEETCODE_PROBLEMS_START / LEETCODE_PROBLEMS_END to PLATFORM_PROBLEMS_START / PLATFORM_PROBLEMS_END.
• Update Prompt (get_explain_prompt):
  • Update instructions inside the prompt to request problem recommendations from LeetCode, GeeksforGeeks, HackerRank, Coding Ninjas, Codolio, and Codeforces.
  • Enforce a strict output format for these problems: Platform | Title | Link.
• Add New Tracking Tags: Add regex tracking markers for:
  • OPTIMIZED_CODE_START / OPTIMIZED_CODE_END
  • OPTIMIZED_TIME_COMPLEXITY_START / OPTIMIZED_TIME_COMPLEXITY_END
  • OPTIMIZED_SPACE_COMPLEXITY_START / OPTIMIZED_SPACE_COMPLEXITY_END
• Enhance Gemini Prompt: Update the prompt to command the AI model to generate the most optimal version of the analyzed code along with its precise complexities.
• Update Parsing (analyze_code): Update the return dictionary keys to extract and return: platform_problems, optimized_code, optimized_time_complexity, and optimized_space_complexity.

test_mock_ai.py

• Update MOCK_EXPLAIN_RESPONSE: Swap out old LeetCode tags for the new PLATFORM_PROBLEMS tags.
• Mock Multi-Platform Data: Add realistic mock problem data showcasing mixed platforms (e.g., GFG, Codeforces, HackerRank) using the Platform | Title | Link pattern.
• Inject Optimization Mock Data: Add mock string segments wrapped in the new optimization tags.

test_features.py

• Fix Assertions: Change verification logic to check for platform_problems instead of leetcode_problems.
• Add Verification Prints: Ensure the test prints the extracted optimized code and complexities to verify the parser works seamlessly.

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Frontend Implementation Tasks

index.html (CSS & HTML Markup)

• Dropdown Styling: Add premium, glassmorphic dark-blue theme CSS styles for a new dropdown element: #dsa-platform-select. Include smooth transitions for :hover and :focus states.
• DSA Section UI: Replace the static "LeetCode Practice Problems" header inside #sec-dsa with a flex container housing the section title and the new #dsa-platform-select dropdown menu.
• Optimization Section UI: Create an "Optimized Code Block" container inside the Optimization Suggestions panel. Add a <pre> element to display the code cleanly, alongside functional "Copy" buttons.

Frontend JavaScript Logic

• Global State: Declare a global tracking variable (e.g., currentPlatformProblems or cachedProblems) to hold the complete parsed array of multi-platform problems.
• Dropdown Event Listener: Monitor changes on #dsa-platform-select to filter and re-render only the problems matching the selected platform (or show all if default).
• Render Pipeline: Update the rendering engine to process the new optimized_code, optimized_time_complexity, and optimized_space_complexity values and inject them into the DOM.

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Acceptance Criteria

1. The AI successfully returns links from multiple coding platforms.
2. Selecting a platform from the frontend dropdown correctly filters the displayed problem links in real-time.
3. The UI perfectly renders a dedicated block displaying the optimized code with its time/space complexity.
4. All backend mock and integration tests pass successfully without breaking existing code analysis tools.