feat(agent): 检索工具、模型接入与结构化回复

Agent 按组织与知识源范围调用检索工具，密钥加密保存，回复含来源与转人工意图。

frontend/src/components/aiagent/onboarding/steps/step-controls.css

@@ -0,0 +1,64 @@
+/*
+Copyright 2024-2026 ReplyPier
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/* Controls shared by the Teach step and the pieces it is built from. Pulled in
+   with <style scoped src> so each component keeps its own scope. */
+
+.btn-soft {
+  flex-shrink: 0;
+  padding: 14px 18px;
+  background: var(--o06);
+  border: 1px solid var(--o14);
+  border-radius: var(--radius-input);
+  color: var(--text);
+  font-size: 14px;
+  font-weight: 500;
+  font-family: var(--font-sans);
+  cursor: pointer;
+  white-space: nowrap;
+  transition: var(--transition-fast);
+}
+
+.btn-soft:hover:not(:disabled) {
+  background: var(--o10);
+}
+
+.btn-text {
+  padding: 14px 8px;
+  background: none;
+  border: none;
+  color: var(--muted2);
+  font-size: 14px;
+  font-family: var(--font-sans);
+  cursor: pointer;
+  transition: var(--transition-fast);
+}
+
+.btn-text:hover:not(:disabled) {
+  color: var(--text3);
+}
+
+.btn-soft:disabled,
+.btn-text:disabled {
+  opacity: 0.6;
+  cursor: not-allowed;
+}
+
+.step-error {
+  margin: 0;
+  font-size: 13.5px;
+  color: var(--error-color);
+}