Ask a foreign manifest whether it can be loaded, not how it was wired

The performance harness runs the candidate's benchmark against a
baseline checkout, so the candidate's validator reads a manifest built
by an older commit. #535 put a rule about the CURRENT build into that
shared validator — the panel graph must not contain the card facade —
and it is false of every build before #535 by construction. The
candidate then refused to load any older baseline: all nine performance
profiles went red at once on the same step, the stable release gate
withheld `houseplan-card.js` from the published v1.75.0, and none of it
was about speed.

assertBundleManifest now answers only the loader's question: paths
exist, nothing is duplicated, graphs reference listed assets, sizes add
up. The topology of the current build moves to assertOwnBundleTopology,
called from bundle-sync.mjs, which materializes our own dist, and from
the unit test that reads dist/houseplan-assets.json. Neither ever looks
at a foreign tree.

Reproduced end to end, not only in a unit: a v1.74.0 worktree built with
its own code, then `node demo/benchmark_large_house.mjs
--target-root=<baseline>` from this tree. Before the change it stops
with «initial panel graph must contain its own stable entry only»; after
it, the profile is captured.

Issue: #537
User-Visible: no

scripts/bundle-sync.mjs

@@ -16,7 +16,7 @@ import {
 import { dirname, relative, resolve } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import {
-  assertBundleManifest, orderedBundlePayload, verifyBundleTree,
+  assertBundleManifest, assertOwnBundleTopology, orderedBundlePayload, verifyBundleTree,
 } from './bundle-tree.mjs';
 
 const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '..');
@@ -38,6 +38,9 @@ const parseManifest = (path) => {
   return parsed;
 };
 const sourceManifest = assertBundleManifest(parseManifest(manifestPath), manifestPath);
+// #537: this script materializes OUR dist, so the topology of the current
+// build is judged here and nowhere in the shared loader-side validator.
+assertOwnBundleTopology(sourceManifest, manifestPath);
 const managedFiles = [MANIFEST_NAME, ...sourceManifest.files.map((file) => file.path)];
 const sha256 = (path) => createHash('sha256').update(readFileSync(path)).digest('hex');
 const contained = (root, name) => {

scripts/bundle-tree.mjs

@@ -35,6 +35,34 @@ const assertUniqueGraph = (manifest, field, listed, label) => {
   return graph;
 };
 
+/**
+ * Topology of the CURRENT build, checked only against our own tree (#537).
+ *
+ * `assertBundleManifest` above answers «can this manifest be loaded»: paths
+ * exist, nothing is duplicated, graphs reference listed assets, sizes add up.
+ * That question is also asked about FOREIGN trees — the performance harness
+ * runs the candidate's benchmark against a baseline checkout, so the
+ * candidate's validator reads a manifest built by an older commit.
+ *
+ * «Is the panel wired the way we decided today» is a different question, and
+ * #535 proved the cost of confusing them: the rule «the panel graph does not
+ * contain the card facade» is true of every build since #535 and false of
+ * every build before it, so putting it in the shared validator made the
+ * candidate refuse to LOAD any older baseline. All nine performance profiles
+ * went red at once, and the release gate withheld an asset from a published
+ * stable release. Topology belongs here, where only our own dist is judged.
+ */
+export function assertOwnBundleTopology(manifest, label = BUNDLE_MANIFEST) {
+  const initialPanel = manifest?.initialPanelFiles;
+  if (!Array.isArray(initialPanel)) {
+    throw new Error(`${label}: initialPanelFiles must be an array of bundle paths`);
+  }
+  if (initialPanel.includes(CARD_ENTRY)) {
+    throw new Error(`${label}: initial panel graph must not contain the card facade`);
+  }
+  return manifest;
+}
+
 /** Validate the additive two-entry manifest contract independently of disk I/O. */
 export function assertBundleManifest(manifest, label = BUNDLE_MANIFEST) {
   if (manifest?.schema !== 1 || typeof manifest.fingerprint !== 'string'
@@ -63,13 +91,8 @@ export function assertBundleManifest(manifest, label = BUNDLE_MANIFEST) {
   if (!initialView.includes(CARD_ENTRY) || initialView.includes(PANEL_ENTRY)) {
     throw new Error(`${label}: initial View graph must contain only the card stable entry`);
   }
-  // #535: the panel reaches the implementation by its content-hashed name, so
-  // the card's stable facade is no longer part of what the panel loads. That is
-  // the point: the facade is the one address with no version in it, and the
-  // panel must not depend on a URL a browser may keep for hours. What still has
-  // to hold is that the panel reuses the exact card IMPLEMENTATION graph.
-  if (initialPanel.includes(CARD_ENTRY) || !initialPanel.includes(PANEL_ENTRY)) {
-    throw new Error(`${label}: initial panel graph must contain its own stable entry only`);
+  if (!initialPanel.includes(PANEL_ENTRY)) {
+    throw new Error(`${label}: initial panel graph must contain its own stable entry`);
   }
   if (initialView.some((path) => path !== CARD_ENTRY && !initialPanel.includes(path))) {
     throw new Error(`${label}: initial View implementation is not a subset of initial panel graph`);

scripts/mutation-gate.mjs

@@ -3124,6 +3124,25 @@ const MUTANT_DEFINITIONS = [
       replace: '      void panelEntry; // mutant: cached panel keeps its static shared-chunk import',
     }],
   },
+  {
+    id: 'manifest-loader-judges-current-topology',
+    guard: 'node --test --test-name-pattern="#537 loader-side validation" '
+      + 'test/bundle-assets.test.mjs',
+    because: 'the loader-side validator also reads FOREIGN manifests — the performance harness '
+      + 'runs the candidate against a baseline checkout — so a rule about how the CURRENT build '
+      + 'is wired makes the candidate refuse to load any older baseline. That is what turned all '
+      + 'nine performance profiles red at once and withheld an asset from a published stable '
+      + 'release (#537)',
+    patches: [{
+      file: 'scripts/bundle-tree.mjs',
+      find: '  if (!initialPanel.includes(PANEL_ENTRY)) {\n'
+        + '    throw new Error(`${label}: initial panel graph must contain its own stable entry`);\n'
+        + '  }',
+      replace: '  if (initialPanel.includes(CARD_ENTRY) || !initialPanel.includes(PANEL_ENTRY)) {\n'
+        + '    throw new Error(`${label}: initial panel graph must contain its own stable entry`);\n'
+        + '  }',
+    }],
+  },
   {
     id: 'panel-imports-unversioned-card-entry',
     guard: 'node --test --test-name-pattern="#486 both stable entries" '