fix(factory-plugin): wire marketplace so droid installs the Factory plugin

Add .factory-plugin/marketplace.json sourcing ./gitnexus-factory-plugin.
Droid reads it before .claude-plugin/marketplace.json, so
`droid plugin install` now delivers the Factory plugin (Execute matcher,
pinned mcp.json) instead of the translated Claude plugin (Bash matcher,
gitnexus@latest). Register the surface in the version-sync script and
cover the wiring in the factory and sync test suites.

.factory-plugin/marketplace.json

@@ -0,0 +1,19 @@
+{
+  "name": "gitnexus-marketplace",
+  "owner": {
+    "name": "GitNexus",
+    "email": "nico@gitnexus.dev"
+  },
+  "metadata": {
+    "description": "Code intelligence powered by a knowledge graph — execution flows, blast radius, and semantic search",
+    "homepage": "https://github.com/nicosxt/gitnexus"
+  },
+  "plugins": [
+    {
+      "name": "gitnexus",
+      "version": "1.6.9",
+      "source": "./gitnexus-factory-plugin",
+      "description": "Code intelligence powered by a knowledge graph. Provides execution flow tracing, blast radius analysis, and augmented search across your codebase."
+    }
+  ]
+}

gitnexus/scripts/sync-plugin-manifests.mjs

@@ -15,6 +15,7 @@
  *   - gitnexus-claude-plugin/skills/<skill>/mcp.json      (gitnexus@<version> launch arg, x10)
  *   - gitnexus-factory-plugin/.factory-plugin/plugin.json (top-level version)
  *   - gitnexus-factory-plugin/mcp.json                    (gitnexus@<version> launch arg)
+ *   - .factory-plugin/marketplace.json                    (plugins[gitnexus])
  *
  * Modes:
  *   node scripts/sync-plugin-manifests.mjs           rewrite stale surfaces
@@ -62,6 +63,10 @@ const MANIFEST_SURFACES = [
   // released CLI.
   { file: 'gitnexus-factory-plugin/.factory-plugin/plugin.json', kind: 'plugin' },
   { file: 'gitnexus-factory-plugin/mcp.json', kind: 'mcp' },
+  // Droid reads .factory-plugin/marketplace.json before .claude-plugin's, so
+  // this entry is what makes `droid plugin install` deliver the Factory plugin
+  // (Execute matcher, pinned mcp.json) instead of the translated Claude one.
+  { file: '.factory-plugin/marketplace.json', kind: 'marketplace' },
 ];
 
 const PLUGIN_NAME = 'gitnexus';

gitnexus/test/unit/factory-plugin.test.ts

@@ -64,6 +64,23 @@ describe('Factory plugin files', () => {
   });
 });
 
+// ─── Marketplace wiring ─────────────────────────────────────────────
+
+// Droid reads .factory-plugin/marketplace.json before .claude-plugin's, so this
+// is what makes `droid plugin install` deliver this Factory plugin instead of
+// the translated Claude one (Bash matcher, gitnexus@latest MCP).
+describe('Factory marketplace wiring', () => {
+  const marketplace = JSON.parse(
+    fs.readFileSync(path.join(REPO_ROOT, '.factory-plugin', 'marketplace.json'), 'utf-8'),
+  );
+
+  it('exposes a single gitnexus plugin sourced from ./gitnexus-factory-plugin', () => {
+    const entries = marketplace.plugins.filter((p: { name: string }) => p.name === 'gitnexus');
+    expect(entries).toHaveLength(1);
+    expect(entries[0].source).toBe('./gitnexus-factory-plugin');
+  });
+});
+
 // ─── Drift guard: bundled guards === canonical Claude copies ─────────
 
 describe('Factory plugin bundled guards stay in lockstep with the Claude adapter', () => {

gitnexus/test/unit/sync-plugin-manifests.test.ts

@@ -10,6 +10,7 @@ const SURFACES = [
   'gitnexus-claude-plugin/.codex-plugin/plugin.json',
   '.agents/plugins/marketplace.json',
   'gitnexus-factory-plugin/.factory-plugin/plugin.json',
+  '.factory-plugin/marketplace.json',
 ] as const;
 
 const FACTORY_MCP = 'gitnexus-factory-plugin/mcp.json';
@@ -60,6 +61,10 @@ function makeRoot(packageVersion: string, manifestVersion: string): string {
     plugins: [{ name: 'gitnexus', version: manifestVersion, category: 'Developer Tools' }],
   });
   writeJson(root, SURFACES[4], { name: 'gitnexus', version: manifestVersion });
+  writeJson(root, SURFACES[5], {
+    name: 'gitnexus-marketplace',
+    plugins: [{ name: 'gitnexus', version: manifestVersion, source: './gitnexus-factory-plugin' }],
+  });
   for (const dir of [...MCP_SKILL_DIRS.map(mcpPath), FACTORY_MCP]) {
     writeJson(root, dir, {
       mcpServers: {