kernel->instance vocab migration lane anchor (T218 D6)

docs/design/20260607-t218-kernel-to-instance-vocab.md

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+# Runtime lane — `kernel` → `instance` vocab migration (T=218)
+
+> **Status: BRANCH ANCHOR / intent note. No code rename in this commit.**
+> This branch (`feat/manifold-instances-vocab`) is the authoring lane for the runtime side of the
+> 4.0 `kernel→instance` rename (delta **D6**). Authored by the Z440 VS Code lead
+> (`agent:vscode.hp-z440.primary` / `session:sam.z440-vscode-projection-lead`), 2026-06-07.
+> Glued to `ffs0` branch `z440-vscode-lead/manifold-instances-vocab` and its design doc
+> `dev/design/20260607-t218-manifold-instance-vocab-delta.md` via the shared purpose-slug
+> **`manifold-instances-vocab`**.
+
+## Why this branch exists
+
+Per T=218 branching doctrine, runtime work in `moos-kernel` always lands on `feat/<purpose-slug>`, keyed
+to a feature session, and merges to `master` only when the build gate passes. This lane tracks the
+`kernel → instance` rename so it converges as one reviewed unit instead of leaking across trunk commits.
+
+`instance := fold(log)` exposed at an endpoint — the same object the README already describes as "the
+kernel is a fold over the log". The rename is a **label** change; §M11/§M12 authority semantics and the
+rewrite set (ADD/LINK/MUTATE/UNLINK) are unchanged.
+
+## Runtime footprint to migrate (survey — NOT yet changed)
+
+- `internal/kernel/` package name + all import paths.
+- `/healthz` and `/state/*` payload field names that say `kernel`.
+- `cmd/moos` flags / log lines referring to "kernel".
+- README.md / CLAUDE.md prose.
+- URN handling for `urn:moos:kernel:<ws>.<name>`.
+
+## Migration discipline
+
+- **Alias-first.** The runtime must accept both `kernel` and `instance` forms simultaneously across the
+  transition so federation/readback and the router never break mid-migration. URN form stays readable as
+  `urn:moos:kernel:<ws>.<name>` until a reviewed URN migration ships.
+- **Build gate = apply gate (T=218).** No rename merges to `master` until the Doctor check (the ffs0
+  `dev/scripts/ops/Test-MoosFederation.ps1 -Mode Doctor` federation health gate) + `go test ./...` pass
+  on this branch.
+- **Boundary.** This branch carries data (this note). Its existence emits no hypergraph (HG) rewrite, no
+  deploy, no rename. It is S0 substrate until reviewed and merged with a provenance trailer:
+  `authored-by: agent:vscode.hp-z440.primary / session:sam.z440-vscode-projection-lead / manifold-instances-vocab`.