fix: harden container config DB layer

- config-add/remove-package now rebuild image + restart containers
- Deduplicate packages in self-mod install_packages handler
- Add runtime whitelist guards for SQL column interpolation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/modules/self-mod/apply.ts

@@ -30,15 +30,19 @@ export const applyInstallPackages: ApprovalHandler = async ({ session, payload,
     return;
   }
 
-  // Append new packages to existing lists in the DB
+  // Append new packages to existing lists in the DB (deduplicated)
   if (payload.apt) {
     const existing = JSON.parse(configRow.packages_apt) as string[];
-    existing.push(...(payload.apt as string[]));
+    for (const pkg of payload.apt as string[]) {
+      if (!existing.includes(pkg)) existing.push(pkg);
+    }
     updateContainerConfigJson(agentGroup.id, 'packages_apt', existing);
   }
   if (payload.npm) {
     const existing = JSON.parse(configRow.packages_npm) as string[];
-    existing.push(...(payload.npm as string[]));
+    for (const pkg of payload.npm as string[]) {
+      if (!existing.includes(pkg)) existing.push(pkg);
+    }
     updateContainerConfigJson(agentGroup.id, 'packages_npm', existing);
   }