feat: add save feedback prompts, featured agent fields, dynamic Dify API config, and chat improvements

- Add success/error feedback messages near submit buttons in all admin forms
- Display success prompt for 1s before redirect after save
- Show API error details on save failure
- Add isFeatured/featuredOrder fields to Agent model and admin UI
- Add difyApiUrl/difyApiKey fields for per-agent Dify API configuration
- Show featured badge column in agent admin list
- Display featured agents on homepage sorted by order
- Refactor chat page streaming with AbortController and stable userId
- Improve Dify API proxy to use per-agent credentials

prisma/migrations/20260508102405_add_featured_fields/migration.sql

@@ -0,0 +1,29 @@
+-- RedefineTables
+PRAGMA defer_foreign_keys=ON;
+PRAGMA foreign_keys=OFF;
+CREATE TABLE "new_Agent" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "name" TEXT NOT NULL,
+    "slug" TEXT NOT NULL,
+    "description" TEXT NOT NULL,
+    "icon" TEXT,
+    "categoryId" INTEGER,
+    "features" TEXT NOT NULL DEFAULT '',
+    "hotQuestions" TEXT NOT NULL DEFAULT '[]',
+    "quickQuestions" TEXT NOT NULL DEFAULT '[]',
+    "difyApiUrl" TEXT,
+    "difyApiKey" TEXT,
+    "usageCount" INTEGER NOT NULL DEFAULT 0,
+    "status" TEXT NOT NULL DEFAULT 'active',
+    "isFeatured" BOOLEAN NOT NULL DEFAULT false,
+    "featuredOrder" INTEGER NOT NULL DEFAULT 0,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" DATETIME NOT NULL,
+    CONSTRAINT "Agent_categoryId_fkey" FOREIGN KEY ("categoryId") REFERENCES "Category" ("id") ON DELETE SET NULL ON UPDATE CASCADE
+);
+INSERT INTO "new_Agent" ("categoryId", "createdAt", "description", "features", "icon", "id", "name", "slug", "status", "updatedAt", "usageCount") SELECT "categoryId", "createdAt", "description", "features", "icon", "id", "name", "slug", "status", "updatedAt", "usageCount" FROM "Agent";
+DROP TABLE "Agent";
+ALTER TABLE "new_Agent" RENAME TO "Agent";
+CREATE UNIQUE INDEX "Agent_slug_key" ON "Agent"("slug");
+PRAGMA foreign_keys=ON;
+PRAGMA defer_foreign_keys=OFF;