Install orjson with the logging and *-all extras where it has wheels #339

lite-bootstrap renders log lines with orjson when it is installed and falls back to stdlib json otherwise (lite_bootstrap/instruments/logging_factory.py:48-51). Only the separate orjson extra installs it (pyproject.toml, orjson>=3.8.0 since #328); logging is structlog only and no *-all extra pulls it. So a default lite-bootstrap[fastapi-all] install takes the slower path.

Measured on 2026-10-24 at 705d8a3 on Linux with 2 CPUs (CPython 3.14.9, output to /dev/null, 50000 calls per round): a log.info(...) call through lite-bootstrap's chain costs 9.5 µs with orjson and 11.5 µs with stdlib json, about 2 µs per log call. In isolation JSONRenderer costs 0.49 µs with orjson against 2.16 µs with compact stdlib json. The tables and scripts are to be published with #335.

The blocker is ADR-0004. orjson has no free-threaded wheels and refuses to build on a free-threaded interpreter, and the ADR records that "PEP 508 has no environment marker for 'GIL enabled', so neither can be required conditionally". That is why orjson is opt-in today. Adding it to logging and the *-all extras needs a marker that skips free-threaded builds, and the ADR says there is none. Also, orjson 3.13.0 (the newest on PyPI on 2026-10-24) ships cp314 wheels but none for cp314t or cp315.

Work

• First establish whether a marker exists now: check the current dependency-specifier spec on packaging.python.org and the status of any PEP adding an ABI-feature marker, and whether pip and uv both evaluate it. Record the answer here before writing code.
• If one exists: add orjson>=3.8.0; <marker for GIL-enabled builds> to logging and to each *-all extra, supersede ADR-0004's orjson half with a new ADR, and add a step to the free-threaded CI job that installs logging and checks that orjson is absent. Consider also excluding interpreters orjson has no wheel for (3.15 today), or say why a source build there is acceptable.
• If none exists: close this issue, and add one sentence to docs/introduction/installation.md recommending [orjson] next to [logging] on GIL builds, with the 2 µs figure.

Verify: on CPython 3.14, uv pip install lite-bootstrap[fastapi-all] installs orjson; on 3.14t the same install succeeds without it; the suite passes on both.

Not breaking: the GIL fast path is byte-for-byte the same output (ADR-0004), and free-threaded installs are unchanged.