PROJECT_GUIDELINES.md had drifted out of reality (podman-only rule
while the stack runs docker; verifier scripts wired to Makefile targets
nobody runs). Trashed it, its two verifier scripts, and the Makefile
targets; the rules that still matched reality (docker runtime, schema
in place until release, server binary only via Docker, services layer,
integration-test pool rules) are absorbed into the new AGENTS.md.
The library-visibility family-lens rule now has a real home:
- AGENTS.md: the standing rule agents auto-discover (new media
endpoints MUST thread the visible-library set; 403, never silently
pass; history of the 2026-10-13 leak).
- docs/developer/library-visibility.md: the full explanation (helpers,
SQL pattern, per-item content gates, series per-library), linked
from the developer docs index.
Stale doc links updated (docs index, contributing, development).
