[FEATURE] UI Leaderboard should indicate the total assessments count with the submission score

[kami619]

Problem Statement

With the fix for issue #309, leaderboard submissions can now include assessments with fewer than 25 attributes (when --exclude is used). However, users viewing the leaderboard have no way to know if a submission used exclusions, making it difficult to compare scores fairly.

Proposed Solution

Add a visual indicator on the leaderboard UI to show when a submission has excluded attributes. This could be:

• A badge or icon next to the score (e.g., "22/25 attributes")
• A tooltip explaining which attributes were excluded
• A filter option to show only full assessments (25/25)

Alternatives Considered

1. Reject exclusions for leaderboard — Too restrictive; some attributes may not apply to all projects
2. Separate leaderboards — Full vs. partial assessments; adds complexity
3. Score normalization — Adjust scores based on attributes assessed; could be misleading

Use Cases

1. User wants to compare their full assessment against others and filter out partial submissions
2. User wants to understand why a project has a high score with fewer attributes
3. Maintainer wants to identify trends in which attributes are commonly excluded

Additional Context

Related to issue #309 (schema validation fix) which enabled partial assessments to be submitted.

The attributes_total and attributes_assessed fields are already present in the assessment JSON, so no data changes are needed — only UI updates.

Acceptance Criteria

• Leaderboard shows attribute count (e.g., "22/25") for each submission
• Submissions with < 25 attributes have a visual indicator (badge, icon, or color)
• Optional: Filter to show only full assessments (25/25)
• Optional: Tooltip showing which attributes were excluded (if available in metadata)

Priority

• Medium (nice to have)