Fix sidebar accordion action spacing

[DhruvShah-Dev]

Summary

• Fixes [Feat]: Refresh and Add Table buttons are difficult to select when scroll bars appear #310 by reserving a padded action lane in sidebar accordion headers.
• Keeps refresh/add controls away from the scrollbar edge while allowing long section titles to truncate instead of squeezing action buttons.
• Adds a focused regression test for the action-lane spacing contract.

Validation

• pnpm.cmd test tests/components/layout/sidebar/Accordion.test.tsx --run
• pnpm.cmd typecheck
• pnpm.cmd lint
• pnpm.cmd build
• git diff --check
• GitNexus impact and detect-changes: low risk, expected accordion/test files only

Note: rendered browser validation was not run because the Browser plugin is unavailable and this repo does not include Playwright.

[DhruvShah-Dev]

Kilo Code Review timed out on this PR. Local validation passed: focused Accordion test, typecheck, lint, production build, git diff check, and GitNexus low-risk change detection. Happy to address any concrete review feedback if the bot rerun succeeds.