feat(reports): add BaseReport + 4 concrete report classes

[ldastey-dev]

Action 10 — Report Classes

What this PR does

Introduces src/chesscom/reports/ — a layered report abstraction that replaces the business logic in all four legacy scripts.

Class hierarchy

BaseReport (ABC)
├── MemberSummaryReport      ← generate_club_member_report.py
├── ProspectReport           ← generate_prospect_data.py
├── MatchEligibilityReport   ← match_strengthening_extract.py
└── MatchParticipationReport ← club_contribution_report.py

BaseReport contract

Method	Type	Responsibility
collect_data()	abstract	Fetch + transform via ChessComClient
get_report_name()	abstract	Base filename / sheet name
build_sheet_configs(data)	concrete (overridable)	Maps data → SheetConfig list
run()	concrete	Orchestrates the pipeline, returns path

Report highlights

MemberSummaryReport — single sheet, Member.from_api_response for clean domain objects, joined timestamp passed from club-members endpoint.

ProspectReport — exclusion and deduplication at the raw-username level before fetching full profile/stats, avoiding wasted API calls for excluded members.

MatchEligibilityReport — uses filter_members_by_rating service; sheet name includes variant (CHESS / CHESS960); raises ValueError when match_id absent.

MatchParticipationReport — two-sheet workbook (Member Metrics + Match Data); uses build_participation_stats service; per-match result columns injected into Match Data sheet; raises ValueError when data_analysis_year absent.

All reports: no raw requests calls, no utils dependency, no module-level env vars.

Tests (41 new → 255 total)

Each report class has a dedicated test class using MagicMock for the client:

• Report name, column presence, data accuracy
• Exclusion / deduplication / filtering logic
• Error paths (missing match_id, missing year)
• build_sheet_configs sheet count / naming
• run() integration tests using tmp_path