wip: tool call structure investigation and e2e tests

- Add debug logging for tool call payloads in agent-stream-view
- Add e2e tests to verify tool call structure for Claude and Codex agents
- Include sidebar toggle and horizontal scroll improvements from previous work

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/app/src/constants/layout.ts

@@ -1 +1,6 @@
 export const FOOTER_HEIGHT = 75;
+
+// Shared header inner height (excluding safe area insets and border)
+// Used by both agent header (ScreenHeader) and explorer sidebar header
+// This ensures both headers have the same visual height
+export const HEADER_INNER_HEIGHT = 48;