New business functions have been added

[Gotnhub]

Summary

Add a new business logger utility to spdlog that routes logs into different files based on business type.
Each business type writes to its own rotating log file, with 30MB max per file and up to 3 files retained.

Supported business types:

• Screen recording
• Desktop opening
• Keyboard recording
• Audio recording

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Motivation / Background

In some applications we need to separate logs by business domain to make troubleshooting easier.
This PR introduces a small business logging layer on top of spdlog, allowing callers to pass a business tag/type and have logs automatically written to the corresponding log file with rotation/retention.

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What’s included

New files

• include/spdlog/business_logger.h
  Defines business types and the BusinessLogger manager API.
• src/business_logger.cpp
  Implements the business logger manager and sink/file creation.
• example/business_logger_example.cpp
  Demonstrates usage and generates expected business log files.
• tests/test_business_logger.cpp
  Catch2 tests validating business log routing and setup.

Modified files

• include/spdlog/spdlog.h
  Includes business_logger.h so users can access the new feature by including <spdlog/spdlog.h>.
• CMakeLists.txt
  Adds src/business_logger.cpp into the build.
• example/CMakeLists.txt
  Adds build target for business_logger_example (and removes duplicate entries introduced during iteration).
• tests/CMakeLists.txt
  Adds test_business_logger.cpp into the unit test target.

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API / Usage

Typical usage:

• Call spdlog::business::BusinessLogger::instance().log(...)

• Provide business type + message (supports multiple log levels: trace/debug/info/warn/err/critical)

• Logs are routed into per-business files, with rotation:

  • max file size: 30MB
  • max files per business: 3

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How to test

Build + run example + run tests:

cd build
cmake .. -DSPDLOG_BUILD_TESTS=ON
make
./example/business_logger_example
./tests/spdlog-utests

Expected result:

• Example runs successfully and creates per-business log files (e.g. screen_recording.txt, desktop_opening.txt, keyboard_recording.txt, audio_recording.txt depending on the configured naming/path).
• Unit tests pass via spdlog-utests.

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Notes

• src/spdlog.cpp was reviewed and not modified (it mainly contains template instantiations); build integration is handled via CMake instead.
• Fixed a build issue in the example by adding missing <iostream> include.

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Checklist

• Added new feature (business log routing)
• Added example demonstrating usage
• Added unit tests (Catch2)
• Integrated into build system (CMake)
• Verified by local build + running example + running tests