fix(plugin-sdk): scan dependency tree before materialising openclaw symlink

The dependency-tree security scan rejects node_modules symlinks whose
targets resolve outside the install root. Our trusted host-to-plugin
symlink violates that rule by design, so running the scan AFTER
linkOpenClawPeerDependencies would fail every install with
SECURITY_SCAN_FAILED.

Reorder afterInstall so the scan runs first (walking only the plugin's
own staged source, catching any pre-existing malicious openclaw-named
symlink a source might smuggle in), then the trusted link is
materialised on the now-safe tree.

Also use braces on guard clauses in the new unit tests to satisfy the
oxlint no-unreachable-single-statement-if rule.

src/plugins/install.test.ts

@@ -2387,7 +2387,9 @@ describe("linkOpenClawPeerDependencies (via installPluginFromDir)", () => {
     const { result } = await installFromDirWithWarnings({ pluginDir, extensionsDir });
 
     expect(result.ok).toBe(true);
-    if (!result.ok) return;
+    if (!result.ok) {
+      return;
+    }
 
     const symlinkPath = path.join(result.targetDir, "node_modules", "openclaw");
     const stat = fs.lstatSync(symlinkPath);
@@ -2404,7 +2406,9 @@ describe("linkOpenClawPeerDependencies (via installPluginFromDir)", () => {
     const { result } = await installFromDirWithWarnings({ pluginDir, extensionsDir });
 
     expect(result.ok).toBe(true);
-    if (!result.ok) return;
+    if (!result.ok) {
+      return;
+    }
 
     const nodeModulesDir = path.join(result.targetDir, "node_modules");
     const symlinkPath = path.join(nodeModulesDir, "openclaw");
@@ -2431,7 +2435,9 @@ describe("linkOpenClawPeerDependencies (via installPluginFromDir)", () => {
     expect(second.ok).toBe(true);
     expect(warnings).toHaveLength(0);
 
-    if (!second.ok) return;
+    if (!second.ok) {
+      return;
+    }
     const symlinkPath = path.join(second.targetDir, "node_modules", "openclaw");
     expect(fs.lstatSync(symlinkPath).isSymbolicLink()).toBe(true);
   });

src/plugins/install.ts

@@ -836,15 +836,13 @@ async function installPluginFromPackageDir(
       }
     },
     afterInstall: async (installedDir) => {
-      // Symlink any openclaw peerDependencies into the plugin's node_modules/
-      // so that plugins declaring openclaw as a peerDependency (rather than a
-      // regular dependency) can resolve it at runtime.
-      await linkOpenClawPeerDependencies({
-        installedDir,
-        peerDependencies: peerDeps,
-        logger,
-      });
-      return await runInstallSourceScan({
+      // Run the dependency-tree security scan BEFORE linking peer deps.
+      // The scan rejects any node_modules/ symlink whose target resolves
+      // outside the install root — a rule our trusted host-openclaw link
+      // would fail by design. Running the scan first also keeps the check
+      // honest against malicious plugins, because any pre-existing symlink
+      // smuggled in by the source would still be present when we walk.
+      const scanResult = await runInstallSourceScan({
         subject: `Plugin "${pluginId}"`,
         scan: async () =>
           await runtime.scanInstalledPackageDependencyTree({
@@ -853,6 +851,15 @@ async function installPluginFromPackageDir(
             pluginId,
           }),
       });
+      if (scanResult) {
+        return scanResult;
+      }
+      await linkOpenClawPeerDependencies({
+        installedDir,
+        peerDependencies: peerDeps,
+        logger,
+      });
+      return null;
     },
   });
 }