feat: add event archive and historical query functionality

[Jagadeeshftw]

Summary

Implements event archive and historical query support for resolved/cancelled markets and fixes three existing payout tests that were failing because resolve_market_manual already calls distribute_payouts internally.

Changes

Test fixes (existing failures)

• Cause: resolve_market_manual calls distribute_payouts internally, so a second call saw all winners as claimed and returned 0.
• Update: In test_automatic_payout_distribution, test_market_state_after_claim, and test_integration_full_market_lifecycle_with_payouts:
  • Removed the extra distribute_payouts call.
  • Assert resolution and payout by checking market.state == Resolved and market.claimed for winners/losers.

Event archive and historical query (#271)

Types

• Added EventHistoryEntry in types.rs: public metadata only (no votes, stakes, or addresses) — market_id, question, outcomes, end_time, created_at, state, winning_outcome, total_staked, archived_at, category.

New module: event_archive.rs

• archive_event(env, admin, market_id) — Admin-only; archives a resolved or cancelled market. Uses Error::InvalidState / Error::AlreadyClaimed (no new error variants to stay within #[contracterror] limit).
• is_archived(env, market_id) — Returns whether a market is archived.
• query_events_history(env, from_ts, to_ts, cursor, limit) — Events by creation time range; paginated; limit capped at 30.
• query_events_by_resolution_status(env, status, cursor, limit) — Events by MarketState (e.g. Resolved, Cancelled).
• query_events_by_category(env, category, cursor, limit) — Events by oracle feed_id (category).

Public API in lib.rs

• archive_event(env, admin, market_id) -> Result<(), Error>
• query_events_history(env, from_ts, to_ts, cursor, limit) -> (Vec<EventHistoryEntry>, u32)
• query_events_by_status(env, status, cursor, limit) -> (Vec<EventHistoryEntry>, u32) (name kept ≤ 32 chars)
• query_events_by_category(env, category, cursor, limit) -> (Vec<EventHistoryEntry>, u32)

Security / design

• Archive and query expose only public metadata and outcome; no sensitive data (votes, stakes, addresses).
• Queries are gas-bounded via pagination and MAX_QUERY_LIMIT = 30.
• Existing event storage and resolution behavior is unchanged.

Tests

• Archive: resolved market archive, unauthorized, active market rejected, already archived (success then panic on second archive).
• Queries: time range, by resolution status, by category, pagination, and that EventHistoryEntry contains only public fields.

Testing

• cargo build — success
• cargo test -p predictify-hybrid — 398 tests passed (including 3 fixed payout tests and 10 new archive/query tests)

Closes #271

[Jagadeeshftw]

@greatest0fallt1me review please

[greatest0fallt1me]

Looks great, @Jagadeeshftw! I hope to see more of your work in the future.