Refactor filter logic

[tembo]

Summary

Extracted reusable filter logic into a new filter-helpers.ts module to eliminate duplication across issue and pull request filters. Consolidated status filter definitions and simplified filter matching logic using helper functions and metadata constants.

Changes

• New file: filter-helpers.ts - Extracted extractRepoOptions(), extractAuthorOptions(), repoFilterDef, and authorFilterDef for reuse
• issue-filters.ts: Refactored status filter using issueStatus() helper and ISSUE_STATUS_META constant; removed 86 lines of duplicated code
• pull-filters.ts: Refactored status filter using pullStatus() helper and PULL_STATUS_META constant; removed 89 lines of duplicated code
• pull-detail-sidebar.tsx: Optimized reviewer/team lookups using useMemo Maps instead of .find() calls for O(1) access

Test Plan

• Verify filters work correctly in issue and pull request lists
• Confirm repo and author filters display properly across all views
• Test status filter options render with correct icons and colors
• Validate reviewer toggle performance improvements

Screenshots

Before	After
Duplicated filter logic across files	Centralized, reusable filter helpers

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[tembo]

Requesting review from @stylessh who has experience with the following files modified in this PR:

• apps/dashboard/src/components/filters/pull-filters.ts
• apps/dashboard/src/components/filters/issue-filters.ts
• apps/dashboard/src/components/pulls/detail/pull-detail-sidebar.tsx