Fix health endpoint not reachable through nginx proxy

Move /health to /api/health on backend and update the frontend
feature flag store to match. Without this, the combined Docker
image nginx proxy could not reach the endpoint and feature flags
(chunking/prepare mode) failed to load.

document-parser/main.py

@@ -103,7 +103,7 @@ app.include_router(documents_router)
 app.include_router(analyses_router)
 
 
-@app.get("/health")
+@app.get("/api/health")
 def health():
     """Health check endpoint."""
     return {

document-parser/tests/test_api_endpoints.py

@@ -26,7 +26,7 @@ def mock_analysis_service(client):
 
 class TestHealthEndpoint:
     def test_health(self, client):
-        resp = client.get("/health")
+        resp = client.get("/api/health")
         assert resp.status_code == 200
         data = resp.json()
         assert data["status"] == "ok"

frontend/src/features/feature-flags/store.ts

@@ -44,7 +44,7 @@ export const useFeatureFlagStore = defineStore('feature-flags', () => {
 
   async function load(): Promise<void> {
     try {
-      const data = await apiFetch<HealthResponse>('/health')
+      const data = await apiFetch<HealthResponse>('/api/health')
       engine.value = data.engine
       loaded.value = true
       error.value = null