fix: CSS and a11y in class-detail components

[corypride]

Summary

Three small UX/a11y fixes in frontend/src/pages/class-detail/ surfaced by CodeRabbit on PR #1133. All were preexisting; extracted into named components by Split 3.

• ClassNotFoundCard — Added min-h-screen to the outer wrapper so items-center has a height to center against. Without it the "Class Not Found" card rendered flush to the top of the page. Also corrected Tailwind class order (bg-surface-hover moved after layout utilities).

• LoadingSkeleton — Replaced fixed grid-cols-5 and grid-cols-3 with responsive variants to prevent horizontal overflow on narrow screens:

  • Header: grid-cols-2 sm:grid-cols-3 lg:grid-cols-5
  • Cards: grid-cols-1 sm:grid-cols-2 lg:grid-cols-3

• SessionRow — Added role="button", tabIndex={0}, and an onKeyDown handler (Enter/Space) to the clickable row div so it is reachable and activatable via keyboard. The handler guards with e.target !== e.currentTarget to prevent inner button keypresses (Reschedule, Cancel) from also firing the row's onClick. Also updated 6 flex-shrink-0 → shrink-0 (canonical Tailwind v3 alias).

Test plan

• ClassNotFoundCard renders vertically centered at /program-classes/9999999/detail
• "Back to Classes" navigates to /classes
• LoadingSkeleton header renders 2-col at 375px, 3-col at 768px, 5-col at 1280px
• LoadingSkeleton cards render 1-col at 375px, 2-col at 768px, 3-col at 1280px
• Session rows reachable via Tab with visible focus ring (:focus-visible)
• Enter and Space activate the row action; Space does not scroll the page
• Enter on inner Reschedule/Cancel buttons fires only that button's action, not the row's onClick
• Past and cancelled session rows keyboard accessible
• No console errors during keyboard navigation

Closes #ID-666

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: a3469f4b-cdcd-4e43-ba3f-9622c7870043

📥 Commits

Reviewing files that changed from the base of the PR and between 5f9c489 and 5f9af08.

📒 Files selected for processing (3)

• frontend/src/pages/class-detail/ClassNotFoundCard.tsx
• frontend/src/pages/class-detail/LoadingSkeleton.tsx
• frontend/src/pages/class-detail/SessionRow.tsx

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📝 Walkthrough

Summary by CodeRabbit

• Style

  • Improved layout centering and spacing on the class not found card.
  • Enhanced responsive design for loading placeholders with adaptive column layouts across mobile, tablet, and desktop screens.

• Accessibility

  • Added keyboard navigation support to session rows, enabling interaction via Enter and Space keys.

Walkthrough

This PR updates the class detail page components with styling refinements and accessibility improvements. ClassNotFoundCard container gains min-h-screen sizing, LoadingSkeleton placeholder grids become responsive across breakpoints, SessionRow icons use simplified shrink-0 styling, and the clickable session row becomes keyboard-navigable via Enter and Space keys.

Changes

Class Detail Page UI and Accessibility Improvements

Layer / File(s)	Summary
Container and responsive grid styling frontend/src/pages/class-detail/ClassNotFoundCard.tsx, frontend/src/pages/class-detail/LoadingSkeleton.tsx	ClassNotFoundCard container adds min-h-screen for full-height centering; LoadingSkeleton placeholder grids switch from fixed column counts to responsive breakpoint-based configurations (grid-cols-2 sm:grid-cols-3 lg:grid-cols-5 and grid-cols-1 sm:grid-cols-2 lg:grid-cols-3).
SessionRow icon styling and keyboard accessibility frontend/src/pages/class-detail/SessionRow.tsx	Icon elements updated to use shrink-0 instead of flex-shrink-0; clickable row becomes keyboard-accessible by adding role="button", tabIndex={0}, and an onKeyDown handler that triggers onClick() on Enter or Space keys with proper target validation and default behavior prevention.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main changes: CSS styling fixes and accessibility (a11y) improvements across three class-detail components.
Description check	✅ Passed	The description provides clear, detailed explanations of the three component changes, includes specific CSS and accessibility improvements, and outlines a comprehensive test plan.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[carddev81]

Looks good and tested good.