feat(problems): Upgrade miniinventory V2 with case-insensitive search capability

[TunahanCnrYildiz]

🛠 What was changed?
This PR expands the V2 phase of the miniinventory problem set in strict accordance with the framework's 5-file rule. The core architectural updates include:

• SPEC Expansion: Introduced a new search <query> command to the SPEC-v2.txt document, clearly defining its exact rules, expected output formatting, and fallback error messages.
• Escalated Test Suite: Incorporated a dedicated "Test 8: search product" block into the test-v2.sh testing script. This block rigorously tests the search boundaries, verifying case-insensitive behavior, exact matches, and no-match fallback states.
• Framework Compliance: Cleaned and finalized the problem.json file to ensure the problem strictly adheres to the standard "exactly 5 files" framework constraint.

❓ Why was it changed?

• AI Agent Benchmarking: As part of the V2 problem improvements, these targeted features were added to create a more complex data querying scenario. The primary goal is to heavily measure, stress-test, and challenge the text-filtering and case-insensitive matching capabilities of AI coding agents (codexes) when faced with standard string logic requirements.

✅ Did I test it?

• Syntax & Local Environment: Yes. The test suite (test-v2.sh) was syntax-checked using bash -n and successfully executed manually within a Windows/Git Bash environment.
• Logic Verification: Ensured that the internal bash logic seamlessly navigates boundaries without requiring secondary validation. The script impeccably triggers and catches all expected AI fallback error messages and successful search outputs exactly as dictated by the SPEC.

[seyyah]

Bu PR maalesef projenin AGENT.md belgesindeki kurallara uymadığı için kapatılıyor. Lütfen şartları inceleyerek düzeltmeleri yaptıktan sonra yeni bir PR açın.

This PR is being closed because it violates project conventions:

• PR title "feat(problems): Upgrade miniinventory V2 with case-insensitive search capability" inside invalid format. Title must strictly follow '[component] Brief description' format (e.g., '[problem] Add minipomodoro').

Please review AGENT.md (PR guidelines & New problem checklist) and submit a new PR once the structure matches the conventions.