docs: reserve seam for complete capabilities

packages/host/directory-picker/src/index.ts

@@ -1,5 +1,5 @@
 /**
- * The `ctx.directoryPicker` seam: how the web-GUI host lets an operator
+ * Service Definition for the `ctx.directoryPicker` capability seam: how the web-GUI host lets an operator
  * select a workspace directory. Backends differ in interaction shape, not
  * just mechanism, so the service exposes a discriminated capability instead
  * of one method set: a `native` backend opens one OS chooser on the

packages/host/directory-picker/src/invariant.ts

@@ -10,7 +10,10 @@ export const name = 'host-directory-picker-invariant'
 /** Service required before the companion can reserve package ownership. */
 export const inject = ['invariants']
 
-/** No runtime invariant: this stateless seam owns the capability vocabulary, while backends and the RPC consumer own observations. */
+/**
+ * No runtime invariant: this stateless Service Definition owns the capability
+ * vocabulary, while backends and the RPC consumer own observations.
+ */
 const install: InvariantInstaller = () => {}
 
 /**