docs: auto-update for merged PRs (2026-09-05)

[aheritier]

Keeps /docs in sync with code merged into main in the last 36 hours.

Changes

• docs/configuration/overview/index.md: bumped the documented config schema version from 15 to 16 (both the "Config Versioning" section's "current version" statement and the version-field example), reflecting that config version 15 was frozen and version 16 is now latest.
  • Source: feat(config): freeze v15 and start v16 as latest #4170

Review notes

Every other PR merged in the last 36 hours whose code changes touched user-facing behavior already carried its own doc updates in the same PR (e.g. #4173, #4172, #4169, #4168, #4166, #4151, #4150, #4149, #4145). Those were reviewed for accuracy and completeness against their source diffs and found up to date — no further changes needed. Internal/bugfix-only PRs (#4171, #4167 changelog-only; #4165, #4163, #4161, #4159, #4158, #4157, #4155, #4154, #4153, #4152, #4147) do not change any currently-documented behavior, so /docs was left untouched for those.