@@ -34,6 +34,7 @@ const kernel: WorkspacePackage = {
     ['@agent-device/kernel/device', 'packages/kernel/src/device.ts'],
   ]),
   workspaceDependencies: new Set(),
+  workspaceDevDependencies: new Set(),
   workspaceDependencyField: 'dependencies',
   externalDependencies: new Map(),
 };
@@ -45,6 +46,7 @@ const contracts: WorkspacePackage = {
     ['@agent-device/contracts/interaction', 'packages/contracts/src/interaction.ts'],
   ]),
   workspaceDependencies: new Set(['@agent-device/kernel']),
+  workspaceDevDependencies: new Set(),
   workspaceDependencyField: 'dependencies',
   externalDependencies: new Map(),
 };
@@ -763,15 +765,9 @@ test('the real tree parses, declares, and passes R11', () => {
   // daemon used to own (#2340). The per-file subpaths under `./interaction-*`,
   // `./selector-pipeline*`, `./press-retarget`, `./touch-semantics` are the
   // execution surface the core selector pipeline moved into this package —
-  // one subpath per module so consumers pull only the stage they run; the
-  // `-fixtures` entries are the test-fixture surface (host-kit's
-  // `./audio-probe-fixtures` precedent) — `./interaction-targeting-fixtures`
-  // for the interaction-targeting node trees and `./snapshot-geometry-fixtures`
-  // for the geometry/touch-point builders both this package's and root's
-  // tests build on (#2402, replacing the copy that used to live under root's
-  // `src/__tests__/test-utils/`; it re-exports `makeSnapshotState` from
-  // capture-kit's own `./snapshot-state-fixtures`, its canonical home). Any
-  // other subpath, or the AST leaking into `.`, fails here.
+  // one subpath per module so consumers pull only the stage they run. The `-fixtures`
+  // entries are R83 burn-down, deleted with the export. Any other subpath, or the AST leaking
+  // into `.`, fails here.
   assert.deepEqual([...selectorsPackage.exportTargets.keys()].sort(), [
     '@agent-device/selectors',
     '@agent-device/selectors/absence-observation',
 
@@ -66,7 +66,7 @@ export type WorkspacePackage = {
    * `workspaceDependencyField`. A published package keeps every sibling in `devDependencies`
    * already, so this is empty there.
    */
-  workspaceDevDependencies?: ReadonlySet<string>;
+  workspaceDevDependencies: ReadonlySet<string>;
   /** Where siblings are declared: a published package bundles them, so it lists them as dev-only. */
   workspaceDependencyField: 'dependencies' | 'devDependencies';
   /** Non-workspace dependencies that the root build must externalize. */
@@ -284,7 +284,7 @@ function undeclaredSiblingMessage(
   site: SpecifierSite,
 ): string | undefined {
   if (name === pkg.name || pkg.workspaceDependencies.has(name)) return undefined;
-  const declaredForTests = pkg.workspaceDevDependencies?.has(name) ?? false;
+  const declaredForTests = pkg.workspaceDevDependencies.has(name);
   if (declaredForTests && !isProductionSourceFile(site.file)) return undefined;
   return declaredForTests
     ? `${pkg.name} imports '${site.specifier}' from production source, but ${pkg.dir}/package.json ` +
 
@@ -163,15 +163,14 @@ test('every package tsconfig references exactly its manifest workspace dependenc
         `${pkg.dir}/tsconfig.json references ${dir}, which is not a workspace package`,
       );
     }
+    const declared = new Set([...pkg.workspaceDependencies, ...pkg.workspaceDevDependencies]);
     assert.deepEqual(
       referencedDirs.map((dir) => nameByDir.get(dir)),
-      [...new Set([...pkg.workspaceDependencies, ...(pkg.workspaceDevDependencies ?? [])])]
-        .filter((name) => name !== rootPackageName)
-        .sort(),
+      [...declared].filter((name) => name !== rootPackageName).sort(),
       `${pkg.dir}/tsconfig.json references must equal its manifest workspace:* dependencies and ` +
         `devDependencies`,
     );
-    if (pkg.workspaceDependencies.has(rootPackageName)) {
+    if (declared.has(rootPackageName)) {
       const config = readTsconfig(`${pkg.dir}/tsconfig.json`);
       const paths = (config.compilerOptions?.paths ?? {}) as Record<string, unknown>;
       assert.ok(