feat(agent): SSE — progressive Themen-Tabs (Phase 2)

Der Compliance-Check streamt jetzt progressive Events; der Impressum-Tab
erscheint, sobald das Thema fertig ist, statt am Ende alles auf einmal.
Additiv — das Polling fürs finale Ergebnis bleibt.

- backend: _sse.py (Queue/emit/event_generator) + Endpoint
  /compliance-check/{id}/stream; _update emittiert progress,
  run_agent_outputs emittiert topic (laeuft jetzt frueh nach Phase B),
  Orchestrator emittiert complete/error.
- frontend: SSE-Proxy-Route + EventSource in ComplianceCheckTab merged
  topic-Events in agent_outputs -> Tab erscheint progressiv.
- Tests: backend 5 passed (SSE + agent_outputs); tsc 0 neue Fehler,
  vitest 2 passed, check-loc 0.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

admin-compliance/app/sdk/agent/_components/ComplianceCheckTab.tsx

@@ -1,6 +1,6 @@
 'use client'
 
-import React, { useState, useCallback } from 'react'
+import React, { useState, useCallback, useRef } from 'react'
 import { ComplianceResultTabs } from './ComplianceResultTabs'
 import { DocumentRow } from './DocumentRow'
 import { PreScanWizard, useScanContext, isContextComplete } from './PreScanWizard'
@@ -35,6 +35,9 @@ export function ComplianceCheckTab() {
     if (typeof window === 'undefined') return []
     try { return JSON.parse(localStorage.getItem(STORAGE_KEY_HISTORY) || '[]') } catch { return [] }
   })
+  // SSE: progressive Themen-Tabs (additiv zum Polling).
+  const esRef = useRef<EventSource | null>(null)
+  React.useEffect(() => () => { try { esRef.current?.close() } catch { /* noop */ } }, [])
 
   // Persist URLs and texts (not loading/error state)
   React.useEffect(() => {
@@ -117,6 +120,38 @@ export function ComplianceCheckTab() {
     reader.readAsText(file)
   }, [updateDoc])
 
+  // SSE: füllt agent_outputs progressiv, sobald ein Thema fertig ist.
+  // Das Polling unten liefert weiterhin das finale Gesamtergebnis.
+  const openTopicStream = useCallback((checkId: string) => {
+    try { esRef.current?.close() } catch { /* noop */ }
+    const partial: any = { results: [], agent_outputs: {} }
+    const es = new EventSource(
+      `/api/sdk/v1/agent/compliance-check/${checkId}/stream`,
+    )
+    esRef.current = es
+    es.onmessage = (ev) => {
+      try {
+        const data = JSON.parse(ev.data)
+        if (data.type === 'topic' && data.topic && data.output) {
+          partial.agent_outputs = {
+            ...partial.agent_outputs, [data.topic]: data.output,
+          }
+          setResults((prev: any) =>
+            (prev && Array.isArray(prev.results) && prev.results.length > 0)
+              ? prev                 // finales Ergebnis schon da → behalten
+              : { ...partial },
+          )
+        } else if (data.type === 'progress') {
+          if (data.msg) setProgress(data.msg)
+          if (typeof data.pct === 'number') setProgressPct(data.pct)
+        } else if (data.type === 'complete' || data.type === 'stream_close') {
+          try { es.close() } catch { /* noop */ }
+        }
+      } catch { /* noop */ }
+    }
+    es.onerror = () => { try { es.close() } catch { /* noop */ } }
+  }, [])
+
   const filledCount = Object.values(docs).filter(d => d.url.trim() || d.text.trim()).length
 
   const handleSubmit = async () => {
@@ -157,6 +192,7 @@ export function ComplianceCheckTab() {
       if (!check_id) throw new Error('Keine Check-ID erhalten')
       setActiveCheckId(check_id)
       localStorage.setItem(STORAGE_KEY_CHECK_ID, check_id)
+      openTopicStream(check_id)
 
       // Poll for results (max 25 min = 500 polls x 3s)
       let attempts = 0
@@ -201,6 +237,7 @@ export function ComplianceCheckTab() {
       setError(e instanceof Error ? e.message : 'Unbekannter Fehler')
       setProgress('')
       setProgressPct(0)
+      try { esRef.current?.close() } catch { /* noop */ }
     } finally {
       setLoading(false)
     }