chore: import upstream snapshot with attribution

showcase/integrations/claude-sdk-python/qa/byoc-hashbrown.md

@@ -0,0 +1,49 @@
+# QA: BYOC hashbrown — Claude Agent SDK (Python)
+
+## Prerequisites
+
+- Demo is deployed and accessible
+- Agent backend is healthy (check /api/health)
+- `ANTHROPIC_API_KEY` is set on the deployment
+
+## Test Steps
+
+### 1. Basic Functionality
+
+- [ ] Navigate to `/demos/byoc-hashbrown`
+- [ ] Verify the header "BYOC: Hashbrown" renders
+- [ ] Verify the description paragraph mentions `@hashbrownai/react`
+
+### 2. Feature-Specific Checks
+
+#### Q4 Sales Summary (mixed catalog)
+
+- [ ] Send "Show me a Q4 sales summary" (or click a suggestion)
+- [ ] Verify a `data-testid="metric-card"` renders with a formatted value
+- [ ] Verify a `data-testid="pie-chart"` renders with at least three
+      legend rows
+- [ ] Verify a `data-testid="bar-chart"` renders with at least three
+      columns
+- [ ] Verify at least one Markdown heading renders inline
+
+#### Deal card
+
+- [ ] Ask "Show me a sample deal in the negotiation stage"
+- [ ] Verify a `data-testid="hashbrown-deal-card"` renders with a stage
+      badge
+
+### 3. Streaming behaviour
+
+- [ ] Observe components progressively appear as Claude streams the
+      JSON envelope — no full-refresh flash at the end of streaming
+
+### 4. Error Handling
+
+- [ ] No console errors during normal usage.
+- [ ] No hashbrown schema-validation errors logged.
+
+## Expected Results
+
+- Chat loads within 3 seconds
+- Agent responds within 15 seconds
+- Backend emits the JSON envelope (`{ui: [...]}`), NEVER XML