chore: 初始版本提交 - 简化架构 + 轮询改造

- 移除 Motia Streams 实时通信，改用 3 秒轮询
- 简化前端代码，移除冗余组件
- 简化后端架构，准备 FastAPI 重构
- 更新 pixi.toml 环境配置
- 保留 bttoxin_digger_v5_repro 作为参考文档

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

motia-backend/streams/taskState.ts

@@ -0,0 +1,126 @@
+/**
+ * TaskState Stream Definition
+ *
+ * Manages the state of each task, including overall status and step statuses.
+ * Uses sessionId as groupId for per-task state isolation.
+ *
+ * @see Requirements 5.2, 2.3
+ */
+
+import { defineStream } from '@motia/core'
+import { z } from 'zod'
+
+// Step status enum
+export const StepStatusSchema = z.enum([
+  'PENDING',
+  'RUNNING',
+  'SUCCESS',
+  'FAILED',
+  'SKIPPED',
+])
+export type StepStatus = z.infer<typeof StepStatusSchema>
+
+// Overall task status enum
+export const TaskOverallStatusSchema = z.enum([
+  'QUEUED',
+  'PENDING',
+  'RUNNING',
+  'SUCCESS',
+  'FAILED',
+  'EXPIRED',
+])
+export type TaskOverallStatus = z.infer<typeof TaskOverallStatusSchema>
+
+// Step ID enum
+export const StepIdSchema = z.enum([
+  'upload',
+  'digger',
+  'shotter',
+  'plot',
+  'done',
+])
+export type StepId = z.infer<typeof StepIdSchema>
+
+// Task step schema
+export const TaskStepSchema = z.object({
+  stepId: StepIdSchema,
+  name: z.string(),
+  status: StepStatusSchema,
+  startAt: z.string().nullable(),
+  endAt: z.string().nullable(),
+  durationMs: z.number().nullable(),
+  summary: z.string().nullable(),
+  error: z.string().nullable(),
+})
+export type TaskStep = z.infer<typeof TaskStepSchema>
+
+// Task state schema
+export const TaskStateSchema = z.object({
+  sessionId: z.string(),
+  status: TaskOverallStatusSchema,
+  queuePosition: z.number().nullable(),
+  createdAt: z.string(),
+  startedAt: z.string().nullable(),
+  completedAt: z.string().nullable(),
+  expiresAt: z.string(),
+  error: z.string().nullable(),
+  steps: z.array(TaskStepSchema),
+  resultBundle: z.string().nullable(),
+})
+export type TaskState = z.infer<typeof TaskStateSchema>
+
+
+// Default step names (English)
+export const DEFAULT_STEP_NAMES: Record<StepId, string> = {
+  upload: 'File Upload',
+  digger: 'BtToxin Digger',
+  shotter: 'Shotter Scoring',
+  plot: 'Generate Report',
+  done: 'Package Complete',
+}
+
+// Step order for validation
+export const STEP_ORDER: StepId[] = ['upload', 'digger', 'shotter', 'plot', 'done']
+
+/**
+ * Create initial task state with all steps set to PENDING
+ */
+export function createInitialTaskState(
+  sessionId: string,
+  queuePosition: number | null = null
+): TaskState {
+  const now = new Date()
+  const expiresAt = new Date(now.getTime() + 30 * 24 * 60 * 60 * 1000) // 30 days
+
+  return {
+    sessionId,
+    status: queuePosition !== null ? 'QUEUED' : 'PENDING',
+    queuePosition,
+    createdAt: now.toISOString(),
+    startedAt: null,
+    completedAt: null,
+    expiresAt: expiresAt.toISOString(),
+    error: null,
+    steps: STEP_ORDER.map((stepId) => ({
+      stepId,
+      name: DEFAULT_STEP_NAMES[stepId],
+      status: 'PENDING' as StepStatus,
+      startAt: null,
+      endAt: null,
+      durationMs: null,
+      summary: null,
+      error: null,
+    })),
+    resultBundle: null,
+  }
+}
+
+// Define the taskState stream
+export const taskStateStream = defineStream({
+  name: 'taskState',
+  schema: TaskStateSchema,
+  persistence: {
+    enabled: true,
+    // State is persisted per sessionId (groupId)
+  },
+})