docs: restore media screenshots for mintlify docs

Restore the 5 product screenshots that were previously removed:
- connections-screen.png
- dashboard.png
- secret-manager.png
- workflow-execution.png
- workflow-sample.png

These images are referenced in index.mdx for the product tour section.

Signed-off-by: Aseem Shrey <LuD1161@users.noreply.github.com>

Author: LuD1161