feat: replace print statements with structured logging

[Copilot]

All print() calls in library code (excluding doctest examples) are replaced with a proper logger, following the same pattern used in rf-detr.

New: supervision/utils/logger.py

Introduces _get_logger() (private, internal use only) with:

• DEBUG/INFO → stdout; WARNING+ → stderr
• Configurable via LOG_LEVEL env var (defaults to INFO)
• Idempotent — safe to call multiple times without adding duplicate handlers

Log level assignments

Location	Message	Level
assets/downloader.py	Download start / complete	INFO
assets/downloader.py	MD5 integrity failure	WARNING
utils/video.py	Codec TypeError, falling back to mp4v	WARNING
detection/tools/csv_sink.py	Field name mismatch on append	WARNING
annotators/core.py	Font path not found, using default	WARNING
metrics/mean_average_precision.py	AP/AR summary rows	INFO

Tests

• tests/utils/test_logger.py (new): 11 tests covering logger name, level, LOG_LEVEL env var, stdout/stderr handler configuration, propagate=False, and idempotency.
• tests/assets/test_downloader.py: updated to mock supervision.assets.downloader.logger instead of builtins.print; the corrupted-file test now uses side_effect=[False, True] on is_md5_hash_matching so the real code path (including logger.warning) is exercised and asserted.

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[codecov]

Codecov Report

❌ Patch coverage is 89.74359% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 74%. Comparing base (6ca9555) to head (7e815e6).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #2154   +/-   ##
=======================================
  Coverage       74%     74%           
=======================================
  Files           61      62    +1     
  Lines         7454    7486   +32     
=======================================
+ Hits          5515    5547   +32     
  Misses        1939    1939           

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[Copilot]

Pull request overview

This PR replaces print() statements with structured logging throughout the codebase. It introduces a new internal logging utility (_get_logger()) that configures loggers with separate stdout (INFO/DEBUG) and stderr (WARNING+) handlers. The changes improve observability and allow users to control log output via the LOG_LEVEL environment variable.

Changes:

• Created src/supervision/utils/logger.py with _get_logger() function for consistent logging configuration
• Replaced print() calls with appropriate logger methods (INFO for informational messages, WARNING for issues)
• Updated tests to mock logger instead of builtins.print

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/supervision/utils/logger.py	New module providing _get_logger() function for creating configured loggers
src/supervision/assets/downloader.py	Replaced prints with logger.info (download progress) and logger.warning (file corruption)
src/supervision/metrics/mean_average_precision.py	Replaced print with logger.info for metric summary output
src/supervision/utils/video.py	Replaced print with logger.warning for codec fallback
src/supervision/detection/tools/csv_sink.py	Replaced print with logger.warning for field name mismatch
src/supervision/annotators/core.py	Replaced print with logger.warning for missing font path
tests/assets/test_downloader.py	Updated mocks and assertions to verify logger calls instead of print

[Borda]

@copilot apply changes based on the comments in this thread

[Copilot]

@copilot apply changes based on the comments in this thread

Both items from that review were already applied in 7e815e6: the Example section was added to the _get_logger docstring and tests/utils/test_logger.py was created with 11 tests covering default/custom name, level, LOG_LEVEL env var, stdout/stderr handler wiring, propagate=False, and idempotency.