fix(UX-001): address layout review findings

docs/roadmap/backlog/UX-001-full-width-two-pane-layout.yaml

@@ -1,24 +0,0 @@
-id: UX-001
-title: Full-Width Two-Pane Page Layout
-status: backlog
-priority: P1
-effort: M
-depends_on:
-  - PORT-004
-  - BT-001A
-  - BT-003A
-tags:
-  - ui
-  - layout
-  - nicegui
-summary: Use the full available browser width and standardize primary pages on a 1/3 control-summary pane and 2/3 charts-results pane.
-acceptance_criteria:
-  - Dashboard pages use the full available browser width instead of the current centered max-width container.
-  - Scenario-heavy pages use a consistent desktop two-pane layout with an approximately 1/3 left pane and 2/3 right pane.
-  - Left pane contains controls and summary content; right pane contains charts, tables, and scenario results.
-  - Mobile and narrow widths still stack cleanly without clipping.
-  - Browser-visible tests cover the split-pane structure on representative pages.
-technical_notes:
-  - Likely file targets include `app/pages/common.py`, `app/pages/hedge.py`, `app/pages/backtests.py`, `app/pages/event_comparison.py`, `app/pages/options.py`, and possibly `app/pages/overview.py` / `app/pages/settings.py` for consistent full-width layout.
-  - Prefer shared layout helpers in `app/pages/common.py` over page-specific one-off width classes.
-  - Add stable DOM hooks (for example `data-testid`) so layout structure can be asserted in browser tests.