feat: full-population reviewers/issues/PR ranking (identity in GraphQL, no getUser)

[PrestaEdit]

Summary

Follow-up to #232. Makes the reviewers / issues / pull-requests leaderboards cover every contributor (committers and non-committers) while staying sustainable on GitHub Actions (ephemeral runners, no persistent cache, 5000 req/h).

• Identity captured in the GraphQL fetch — fetch:issues and fetch:pullrequests:all now select author { login avatarUrl url ... on User { name } } (and the same on each review author), so downstream needs no per-user REST call.
• generate:topstats builds a login → {name, avatar_url, html_url} map from the fetched files (buildIdentities()), resolves identity from contributors_prs.json → that map → a minimal fallback, and no longer calls getUser at all.
• Cap removed — the three ranking files now contain everyone with count ≥ 1 (the front keeps a Top-50 highlight and shows the full lists in the Wall of Fame).

Reviews still count distinct PRs (self-reviews excluded, counted even on deleted-author PRs); issues exclude PRs; null authors are skipped for authored counts. contributors_prs.json enrichment is unchanged.

Pairs with PrestaShop/TopContributors#231 (front: Top-50 + Wall-of-Fame tabs).

Test Plan

• phpstan analyse — [OK] No errors
• php-cs-fixer — no diff
• Offline aggregation + identity-map assertion passes (distinct-PR reviews, self-review excluded, null-author handling, fallback identity)
• Live make generate on CI produces full-population top_*.json with zero getUser calls

🤖 Generated with Claude Code