Accessibility and browser-console hygiene

[mrwadams]

Parent

#45 — Harden the scenario-generation journey: persistent state, guided setup, and resilient progress

What to build

Application-owned icon-only controls get meaningful accessible names (Expand sidebar, Collapse sidebar, Send message, Open menu, etc.); every app-owned form control and action is reachable in a logical keyboard order with a visible focus state. The repeated invalid empty sidebar theme-colour warnings are removed via supported Streamlit configuration or a version pin/upgrade rather than brittle DOM/CSS patches, leaving a clean console during normal use. The responsive layout stays overflow-free on a narrow viewport.

Acceptance criteria

• App-owned icon-only controls expose meaningful accessible names; unique form labels; logical keyboard order with visible focus
• The empty sidebar theme-colour console warnings no longer appear on Welcome or a scenario page; any remaining upstream messages are explicitly documented, not silently allowlisted
• No horizontal document overflow at ~390×844; setup, Generate, phase status, result tabs, and result actions remain reachable
• A browser-console smoke check loads Welcome + one scenario page and fails on unexpected application warnings/errors
• An accessibility smoke check asserts accessible names, unique labels, keyboard order, and focus for application-owned controls (not generated Streamlit class names)

Blocked by

• Shared setup sidebar on every scenario page #46 — Shared setup sidebar on every scenario page