Fix settings button edge hit target

[jonathanKingston]

Summary

• keep the entire visible Settings footer above the pane resizer’s invisible overlap
• add an Electron regression assertion for the button’s far-right edge

Testing

• corepack pnpm run check
• corepack pnpm run build
• corepack pnpm run test:e2e -- --spec tests/e2e/portrait-panel-controls.e2e.ts

[github-actions]

🖥️ PR preview

• Marketing site
• Browser demo
  Interactive, with a mocked backend — jump to a scenario:
• Builds a cupcake site
• Agent-proposed edits open the Changes panel
• Markdown list indentation
• Unattended container run
• Responsive composer footer
• Subagent display visual reference
• Subagent stays ungrouped beside reading tools
• Semantic search subagent markdown
• Light-theme approval with a bright accent
• Light-theme syntax, fills, and selection
• Grouped outside-sandbox command approval
• Remote desktop discovered-port list with one selected
• Settings scroll + sticky footer geometry
• Per-model reasoning / temperature / top-p
• Thread switch hydration notice
• Thread switch hydration failure
• Chat layout styling
  _{Static demo of the renderer against a mock API — the browser pane, terminal, and all main-process IPC are stubbed, so it never proves main-process behaviour. Rebuilt whenever a push changes the demo bundle; these links go live once the queued deploy lands, shortly after this comment. Removed when the PR closes.}

[copse-release-bot]

Reference screenshots ready for review

Review GitHub’s image diffs in screenshot PR #2650.
Merge it (or enable auto-merge) to apply the accepted PNGs to codex/settings-button-hit-target-pr.

Rendered for 3ffd2fc76aca by CI run 34511087523; the immutable artifact is reference-screenshot-candidates-34511087523.

If this source branch moves, a later successful render closes the stale review PR and replaces this link.