fix(frontend): 修复合并审阅发现的构建与契约问题

恢复 Vue TypeScript 生产构建，补齐可运行页面壳子，并修复文件树与 SSE 状态问题。

按 FastAPI Wire Contract 统一 Service DTO 映射，同时补充前端开发说明和问题修复复盘。

frontend/src/services/sseClient.ts

@@ -1,3 +1,5 @@
+import { resolveApiUrl } from './apiClient'
+
 export type SseEventHandler = (event: string, data: Record<string, unknown>) => void
 
 export interface SseClientOptions {
@@ -37,7 +39,7 @@ export class SseClient {
         headers['Authorization'] = `Bearer ${token}`
       }
 
-      const resp = await fetch(url, {
+      const resp = await fetch(resolveApiUrl(url), {
         method,
         headers,
         body: body !== undefined ? JSON.stringify(body) : undefined,
@@ -53,6 +55,39 @@ export class SseClient {
       onOpen?.()
 
       const decoder = new TextDecoder('utf-8')
+      let eventName = 'message'
+      let dataLines: string[] = []
+      let doneNotified = false
+
+      const dispatchEvent = () => {
+        if (!dataLines.length) {
+          eventName = 'message'
+          return
+        }
+        try {
+          const data = JSON.parse(dataLines.join('\n')) as Record<string, unknown>
+          onEvent?.(eventName, data)
+          if (!doneNotified && ['Done', 'RunCompleted', 'RunFailed', 'RunCancelled'].includes(eventName)) {
+            doneNotified = true
+            onDone?.()
+          }
+        } catch (error) {
+          onError?.(error instanceof Error ? error : new Error('Malformed SSE data'))
+        }
+        eventName = 'message'
+        dataLines = []
+      }
+
+      const consumeLine = (line: string) => {
+        if (line === '') return dispatchEvent()
+        if (line.startsWith(':')) return
+        const separator = line.indexOf(':')
+        const field = separator === -1 ? line : line.slice(0, separator)
+        let fieldValue = separator === -1 ? '' : line.slice(separator + 1)
+        if (fieldValue.startsWith(' ')) fieldValue = fieldValue.slice(1)
+        if (field === 'event') eventName = fieldValue
+        if (field === 'data') dataLines.push(fieldValue)
+      }
 
       while (true) {
         const { value, done } = await this.reader.read()
@@ -60,39 +95,15 @@ export class SseClient {
 
         this.buffer += decoder.decode(value, { stream: true })
 
-        const lines = this.buffer.split('\n')
+        const lines = this.buffer.split(/\r?\n/)
         this.buffer = lines.pop() || ''
-
-        let eventName = 'message'
-        let dataStr = ''
-
-        for (const line of lines) {
-          const trimmed = line.trim()
-          if (!trimmed) {
-            if (dataStr) {
-              try {
-                const data = JSON.parse(dataStr)
-                onEvent?.(eventName, data)
-                if (eventName === 'Done' || eventName === 'RunCompleted' || eventName === 'RunFailed' || eventName === 'RunCancelled') {
-                  onDone?.()
-                }
-              } catch {
-                /* ignore malformed json */
-              }
-              eventName = 'message'
-              dataStr = ''
-            }
-            continue
-          }
-
-          if (trimmed.startsWith('event:')) {
-            eventName = trimmed.slice(6).trim()
-          } else if (trimmed.startsWith('data:')) {
-            const d = trimmed.slice(5).trim()
-            dataStr += dataStr ? '\n' + d : d
-          }
-        }
+        lines.forEach(consumeLine)
       }
+
+      this.buffer += decoder.decode()
+      if (this.buffer) consumeLine(this.buffer.replace(/\r$/, ''))
+      dispatchEvent()
+      if (!doneNotified) onDone?.()
     } catch (e) {
       if ((e as Error).name === 'AbortError') return
       onError?.(e as Error)