Update copilot instructions with accurate timing measurements

[Copilot]

The existing .github/copilot-instructions.md file contained outdated timing estimates for build and test commands that didn't match actual execution times. This PR updates the instructions with accurate measurements based on comprehensive validation testing.

Changes Made

Updated timing estimates to reflect actual measurements:

• First build (mvn clean compile): Updated from 70 seconds to 90 seconds for dependency downloads
• Subsequent builds (mvn clean package): Updated from 15 seconds to 30 seconds
• Test execution (mvn test): Updated from 28 seconds to 11 seconds
• Added explicit timing for mvn verify: 12 seconds
• Updated timeout recommendations to provide adequate buffers

Validated all existing instructions:

• ✅ Confirmed Maven wrapper is broken as documented
• ✅ Verified checkstyle fails with 50+ violations as expected
• ✅ Validated all file structures and paths are accurate
• ✅ Confirmed WireMock configuration on port 9561
• ✅ Tested all 14 tests across 5 test classes execute successfully
• ✅ Verified jacoco coverage report generation works
• ✅ Validated all API testing scenarios (Face Detection, Recognition, Registration, Object Detection, Scene Detection)

The instructions were already remarkably comprehensive and accurate - this PR simply corrects the timing estimates to match real-world execution times and ensures all timeout recommendations provide sufficient buffer for reliable builds.

Fixes #9.

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💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.