fix(status-tab): improve chart focus, remove duplicate summary, and confine mobile heatmap scroll

MR Title

fix(status-tab): improve chart focus, remove duplicate summary, and confine mobile heatmap scroll

MR Description

Summary

This merge request improves Status Tab clarity and mobile analytics usability by:

• Making missing-status red more distinct in light mode.
• Ensuring Daily "Show Chart" view displays only ring-chart components (no duplicate S1-S4 list).
• Removing duplicate "Daily Pending Summary" from Status Tab.
• Confining Member Activity Heatmap overflow to a dedicated horizontal scroller on mobile.

Related Issue

Closes #33 (closed)

Scope of Changes

• Updated Status Tab rendering conditions for Daily chart mode.
• Removed duplicate pending summary section.
• Adjusted light-mode missing-status tokens only.
• Refactored/updated heatmap container styles for responsive, in-box horizontal scroll.

User Impact

• Cleaner Status Tab with reduced duplication.
• Clearer red for missing standups in light mode.
• Better mobile experience for heatmap browsing without page overflow.

Backward Compatibility

• No breaking API changes.
• No schema or contract changes.
• Dark mode colors intentionally unchanged.

Testing and Validation

• Lint: pass.
• Test suite: pass.
• i18n validation: pass.
• Manual verification:
  • Desktop Status Tab behavior.
  • Mobile heatmap horizontal scrolling confined to heatmap container.

Risk Assessment

Low to Medium.

Potential risks:

• CSS overflow interactions in edge viewport sizes.
• Conditional rendering regressions in Daily Status section.

Mitigations:

• Scoped style changes to heatmap/status sections.
• Existing test suite and lint checks executed.

Rollback Plan

• Revert this MR commit set to restore previous Status Tab and heatmap behavior.

Checklist

• Code follows project conventions.
• No dark mode palette regressions introduced.
• Lint and tests pass locally.
• Scope limited to UI behavior and styling for requested areas.