feat(core/frontend): pipeline stage editor (burn-in controls) + double-submit guard & button greying

Pipeline (脚本→资产→故事板→视频→拼接):
- Stage1 render real script shots + wire 确认脚本→adopt (advance stage)
- Stage2 add person/scene AI-生成 buttons + clickable category tabs
- Stage4 auto-poll videos to completion + per-segment upload + real frame thumbnails + download
- Stage5 real timeline editor: clips undo/redo/split/copy/delete/drag-reorder/zoom,
  subtitle style + per-clip text editor, transition select (xfade preview),
  BGM upload + volume, save draft, export-with-save → shows/download final MP4
- embedded asset URLs everywhere (beat assets pagination)

UX: re-entry guard in action() (no double-submit anywhere) + greyed :disabled
styles for btn-aigen/chat-mode/pill-cta/tl-action so generate buttons visibly
disable while generating.

Also includes prior uncommitted frontend work: settings preferences/sessions/avatar,
asset delete, account/team/products pages, fonts.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/frontend/src/api.ts

@@ -3,7 +3,9 @@ import type {
   Asset,
   AuthPayload,
   BillingSummary,
+  BillingTrend,
   Ledger,
+  LoginSession,
   ModelConfig,
   Notification,
   NotificationList,
@@ -14,7 +16,8 @@ import type {
   ScriptVersion,
   Team,
   TeamMember,
-  User
+  User,
+  UserPreference
 } from "./types";
 
 const API_BASE = import.meta.env.VITE_API_BASE_URL || "";
@@ -75,6 +78,27 @@ export const api = {
   uploadAvatar(formData: FormData) {
     return request<User>("/api/auth/me/avatar/", { method: "POST", body: formData });
   },
+  resetAvatar() {
+    return request<User>("/api/auth/me/avatar/", { method: "DELETE" });
+  },
+  deleteAsset(id: string) {
+    return request<void>(`/api/assets/${id}/`, { method: "DELETE" });
+  },
+  preferences() {
+    return request<UserPreference>("/api/auth/me/preferences/");
+  },
+  updatePreferences(payload: Partial<UserPreference>) {
+    return request<UserPreference>("/api/auth/me/preferences/", { method: "PUT", body: JSON.stringify(payload) });
+  },
+  loginSessions() {
+    return request<LoginSession[]>("/api/auth/me/sessions/");
+  },
+  revokeSession(id: string) {
+    return request<{ revoked: number }>(`/api/auth/me/sessions/${id}/revoke/`, { method: "POST" });
+  },
+  revokeOtherSessions() {
+    return request<{ token: string }>("/api/auth/me/sessions/revoke-others/", { method: "POST" });
+  },
   logout() {
     return request<void>("/api/auth/logout/", { method: "POST" });
   },
@@ -123,6 +147,12 @@ export const api = {
   updateProduct(id: string, payload: Partial<Product>) {
     return request<Product>(`/api/products/${id}/`, { method: "PATCH", body: JSON.stringify(payload) });
   },
+  uploadProductImage(productId: string, formData: FormData) {
+    return request<Product>(`/api/products/${productId}/images/`, { method: "POST", body: formData });
+  },
+  deleteProductImage(productId: string, imageId: string) {
+    return request<Product>(`/api/products/${productId}/images/${imageId}/`, { method: "DELETE" });
+  },
   deleteProduct(id: string) {
     return request<void>(`/api/products/${id}/`, { method: "DELETE" });
   },
@@ -132,7 +162,7 @@ export const api = {
   project(id: string) {
     return request<Project>(`/api/projects/${id}/`);
   },
-  createProject(payload: { name: string; product: string }) {
+  createProject(payload: { name: string; product: string; metadata?: Record<string, unknown> }) {
     return request<Project>("/api/projects/", { method: "POST", body: JSON.stringify(payload) });
   },
   deleteProject(id: string) {
@@ -159,6 +189,12 @@ export const api = {
   generateStoryboard(projectId: string, payload: { prompt: string }) {
     return request(`/api/projects/${projectId}/generate-storyboard/`, { method: "POST", body: JSON.stringify(payload) });
   },
+  pollStoryboard(projectId: string) {
+    return request<{ status: "generating" | "succeeded" | "failed"; done: number; total: number; version_id: string; error?: string }>(
+      `/api/projects/${projectId}/poll-storyboard/`,
+      { method: "POST" }
+    );
+  },
   skipStoryboard(projectId: string) {
     return request<Project>(`/api/projects/${projectId}/skip-storyboard/`, { method: "POST" });
   },
@@ -174,6 +210,24 @@ export const api = {
   submitExport(projectId: string) {
     return request(`/api/projects/${projectId}/submit-export/`, { method: "POST" });
   },
+  pollExport(projectId: string) {
+    return request<import("./types").ExportPoll>(`/api/projects/${projectId}/poll-export/`, { method: "POST" });
+  },
+  uploadVideoSegment(projectId: string, segmentId: string, file: File) {
+    const form = new FormData();
+    form.append("video_segment_id", segmentId);
+    form.append("file", file);
+    return request<Project>(`/api/projects/${projectId}/upload-video-segment/`, { method: "POST", body: form });
+  },
+  uploadBgm(projectId: string, file: File, volume?: number) {
+    const form = new FormData();
+    form.append("file", file);
+    if (volume != null) form.append("volume", String(volume));
+    return request<Project>(`/api/projects/${projectId}/upload-bgm/`, { method: "POST", body: form });
+  },
+  saveTimeline(projectId: string, payload: import("./types").TimelineSavePayload) {
+    return request<Project>(`/api/projects/${projectId}/save-timeline/`, { method: "POST", body: JSON.stringify(payload) });
+  },
   assets() {
     return request<Paginated<Asset>>("/api/assets/");
   },
@@ -186,6 +240,9 @@ export const api = {
   ledgers() {
     return request<Ledger[]>("/api/billing/ledgers/");
   },
+  billingTrend(range?: "day" | "week" | "month") {
+    return request<BillingTrend>(`/api/billing/trend/${range ? `?range=${range}` : ""}`);
+  },
   modelConfigs() {
     return request<Paginated<ModelConfig>>("/api/ai/models/");
   },