[FDE-360] Add stdlib JSON formatter and configure_logging to pylogtracer

[HarvWorks]

Summary

• Adds JSONLogFormatter — stdlib-only logging.Formatter that outputs one JSON object per line matching the Go zap logger schema (timestamp, level, msg, caller, logger, stacktrace)
• Adds configure_logging() — one-call root logger setup with dev/prod dual mode via DEVELOPMENT_MODE env var
• Makes loguru and opentelemetry optional extras — core has zero dependencies
• Fixes pyproject.toml packages config (was ["agents", "models_python"]) and lowers requires-python to >=3.11
• Extracts OpenTelemetry init into tracing_setup.py, lazy-loads optional modules via __getattr__
• Uses single-arg traceback.format_exception() for Python 3.14 compatibility
• Adds 21 tests (formatter + config) with CI workflow and Makefile targets

Addresses reviewer feedback from Hyperdrive PR #1953 to move the JSON log formatter into pylogtracer.

Test plan

• make lint-python passes (ruff format + check)
• make test-python passes (21 tests)
• CI workflow runs and passes
• Verify no internal service names or secrets in any new files (public repo)

🤖 Generated with Claude Code

[HarvWorks]

Addressed all review comments:

1. __init__.py — Removed __getattr__ magic: Replaced with explicit get_structured_logger() and get_tracer() functions that do lazy imports internally.

2. config.py — Removed getattr(logging, ...): Now uses logging.getLevelNamesMapping().get(level_str, logging.INFO).

3. tracing_setup.py — Added boto3 to deps: boto3>=1.35.0 added to the [tracing] optional dependency group in pyproject.toml.

4. tracing_setup.py — Made functions private: Renamed to _get_secret_from_param_store and _create_exporter.

5. tracing_setup.py — Use logging not print: All print() calls replaced with logging.exception() so errors and tracebacks surface in logs. Functions still return None on failure (graceful degradation for non-critical tracing setup), but errors are now clearly visible rather than silently swallowed.