core.md doubled as the folder index: its intro claimed "this folder catalogs the data structures" and carried the 38-row page table, wording that predates the one-page-per-subsystem shape where every page also carries its generated Cordis surface. The folder index now lives in docs/subsystems/README.md (page table plus the type-equiv note), and core.md is one subsystem page among siblings: the spine vocabulary. Structural referents move with it: the docs/AGENTS.md tier table and update rule, development.md's type-equiv pointer, the dsh-code-review skill, the two owning catalog Agent Notes, and website/docs.ts (README projects as reference/subsystems/index.md and takes the docs/subsystems folder alias; sidebar orders shift by one). Remaining "data-structure catalog" / "sub-page" phrasing in active notes and READMEs is reworded to subsystem-page terms in both languages; touched pairs re-recorded; translation-prompt snapshot re-recorded (its example embeds development.md).