An assignment places a module's directories and its accesses (hq 153)

A definition names no host path (ADR 0112); an adopted machine keeps its
data where the predecessor put it. Two settings, validated like endpoints:

  places:   {<directory id>: <path> | {path, owner}}
  accesses: {<access id>: <path>}

An access may now be declared by id (`{"id": "series", "mode": "read-write"}`)
and named in mounts, env and content as ${access:<id>}; the assignment
says where it is on this node, and an access nobody placed is refused by
name. A definition still carrying a path keeps it as the default the
assignment replaces. A placed directory takes the assignment's owner
where it says one. Resolved in composition, so the host receives paths
and owners exactly as before.

internal/catalogue/resolve.go

@@ -791,6 +791,9 @@ func checkResources(modules []Manifest) []string {
 	// which is what lets the stack in 04-ISSUES/036 co-resolve.
 	for _, m := range modules {
 		for _, a := range m.Accesses {
+			if a.Path == "" {
+				continue // placed by the assignment; nothing to compare at registration
+			}
 			switch other := ownedPath[a.Path]; other {
 			case "":
 				// Nobody owns it — the ordinary, correct case for shared data.