fix: auto-expand conflicting files and warn on agent overwrites during import

When importing into an existing company, files with "update" action (conflicts)
now have their parent directories auto-expanded so users immediately see what
will be overwritten. Additionally, server-side warnings are generated for any
agent or project that will be overwritten by the import.

Co-Authored-By: Paperclip <noreply@paperclip.ing>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/services/company-portability.ts

@@ -2042,6 +2042,20 @@ export function companyPortabilityService(db: Db) {
       }
     }
 
+    // Warn about agents that will be overwritten/updated
+    for (const ap of agentPlans) {
+      if (ap.action === "update") {
+        warnings.push(`Existing agent "${ap.plannedName}" (${ap.slug}) will be overwritten by import.`);
+      }
+    }
+
+    // Warn about projects that will be overwritten/updated
+    for (const pp of projectPlans) {
+      if (pp.action === "update") {
+        warnings.push(`Existing project "${pp.plannedName}" (${pp.slug}) will be overwritten by import.`);
+      }
+    }
+
     if (include.issues) {
       for (const manifestIssue of manifest.issues) {
         issuePlans.push({