feat(ai): session persist + continue HTTP/UI, checkpoints, queue

落地 docs/16 P1：会话落盘与真续跑（prior tool 轨迹）、incomplete「加预算继续」、
awaiting_confirm outcome、同参拒+第4/6轮检查点、侧栏忙时单槽排队。
Ask 真 token 流式记缺口（三协议 SSE 成本高）。

src/api.ts

@@ -548,16 +548,49 @@ export type AiAgentRes = {
   stepsBudget?: number;
 };
 
-export async function callAiAgent(payload: {
-  prompt: string;
-  connectionId?: string;
-  driver?: string;
-  database?: string;
-  model?: string;
-}) {
+export async function callAiAgent(payload: AiAgentStreamPayload) {
   return post<AiAgentRes>("/api/ai/agent", payload);
 }
 
+export type AiSessionSummary = {
+  id: string;
+  title?: string;
+  status: string;
+  createdAt: string;
+  updatedAt: string;
+  msgCount: number;
+  lastRunId?: string;
+};
+
+export async function listAiSessions() {
+  return get<{ sessions: AiSessionSummary[] }>("/api/ai/sessions");
+}
+
+export async function getAiSession(id: string) {
+  return get<{
+    id: string;
+    title?: string;
+    status: string;
+    messages: unknown[];
+    runs?: unknown[];
+  }>(`/api/ai/sessions/${encodeURIComponent(id)}`);
+}
+
+export async function continueAiSession(
+  id: string,
+  payload: {
+    prompt?: string;
+    connectionId?: string;
+    driver?: string;
+    database?: string;
+    model?: string;
+    maxRounds?: number;
+    stream?: boolean;
+  },
+) {
+  return post<AiAgentRes>(`/api/ai/sessions/${encodeURIComponent(id)}/continue`, payload);
+}
+
 export type AiAgentQueryResult = {
   columns: string[];
   rows: Record<string, unknown>[];
@@ -579,18 +612,26 @@ export type AiAgentStreamHandlers = {
   onStep?: (step: AiAgentStepExt) => void;
   onDelta?: (delta: string) => void;
   onDone?: (res: AiAgentRes) => void;
+  onIncomplete?: (res: AiAgentRes) => void;
+  onSession?: (meta: { sessionId?: string; runId?: string; runOutcome?: string; resumable?: boolean }) => void;
   onError?: (error: string, partial?: Partial<AiAgentRes>) => void;
 };
 
 /** Agent SSE（stream=true）；不可用时回落非流式。signal 供「停止」。 */
+export type AiAgentStreamPayload = {
+  prompt: string;
+  connectionId?: string;
+  driver?: string;
+  database?: string;
+  model?: string;
+  sessionId?: string;
+  continue?: boolean;
+  maxRounds?: number;
+  prior?: unknown[];
+};
+
 export async function callAiAgentStream(
-  payload: {
-    prompt: string;
-    connectionId?: string;
-    driver?: string;
-    database?: string;
-    model?: string;
-  },
+  payload: AiAgentStreamPayload,
   handlers: AiAgentStreamHandlers,
   signal?: AbortSignal,
 ): Promise<AiAgentRes> {
@@ -636,15 +677,38 @@ export async function callAiAgentStream(
         const d = String(ev.delta || "");
         content += d;
         handlers.onDelta?.(d);
-      } else if (typ === "done") {
+      } else if (typ === "done" || typ === "incomplete") {
         finalRes = {
           content: String(ev.content ?? content),
           sql: ev.sql ? String(ev.sql) : undefined,
           steps: (ev.steps as AiAgentStep[]) || steps,
           rounds: Number(ev.rounds ?? rounds) || 0,
+          runId: ev.runId ? String(ev.runId) : undefined,
+          sessionId: ev.sessionId ? String(ev.sessionId) : undefined,
+          runOutcome: ev.runOutcome ? String(ev.runOutcome) : typ === "incomplete" ? "incomplete" : undefined,
+          incompleteReason: ev.incompleteReason ? String(ev.incompleteReason) : undefined,
+          resumable: !!ev.resumable,
+          stepsBudget: ev.stepsBudget != null ? Number(ev.stepsBudget) : undefined,
         };
         rounds = finalRes.rounds;
-        handlers.onDone?.(finalRes);
+        if (typ === "incomplete") handlers.onIncomplete?.(finalRes);
+        else handlers.onDone?.(finalRes);
+      } else if (typ === "session") {
+        handlers.onSession?.({
+          sessionId: ev.content ? String(ev.content) : ev.sessionId ? String(ev.sessionId) : undefined,
+          runId: ev.runId ? String(ev.runId) : undefined,
+          runOutcome: ev.runOutcome ? String(ev.runOutcome) : undefined,
+          resumable: !!ev.resumable,
+        });
+        if (finalRes) {
+          finalRes = {
+            ...finalRes,
+            sessionId: (ev.content ? String(ev.content) : finalRes.sessionId) || finalRes.sessionId,
+            runId: ev.runId ? String(ev.runId) : finalRes.runId,
+            runOutcome: ev.runOutcome ? String(ev.runOutcome) : finalRes.runOutcome,
+            resumable: ev.resumable != null ? !!ev.resumable : finalRes.resumable,
+          };
+        }
       } else if (typ === "error") {
         handlers.onError?.(String(ev.error || "agent error"), { content, steps, rounds: Number(ev.rounds) || 0 });
       }