feat(contract): support multi-outcome (categorical) markets (#1329)

[AJ0070]

Extends the market model to support multi-outcome (categorical) prediction markets with 2 to N mutually exclusive named outcomes bounded by a configurable maximum cap.

Key Changes

• Configurable Outcome Ceiling: Added DEFAULT_MAX_OUTCOMES (10) constant and max_outcomes: u32 to global Config. Implemented set_max_outcomes admin setter on the contract.
• Market Creation Bounds: Enforced in market::create_market that params.outcomes.len() must be between 2 and cfg.max_outcomes. Creation reverts with InsightArenaError::InvalidInput if outcomes exceed the ceiling or fall below 2.
• Per-Outcome Pool & Staking Tracking: Updated accumulate_outcome_pools to seed all outcome options declared on the market with initial zero stakes, ensuring complete per-outcome visibility in get_outcome_distribution and get_market_stats.
• Resolution & Pro-Rata Payouts: Guaranteed resolution to exactly one valid outcome symbol from outcome_options and pro-rata distribution of the total market pool to winning stakers while strictly conserving total funds.
• End-to-End Tests: Added 3-way, 5-way, and max-outcome validation tests to market_tests.rs.

Acceptance Criteria Checklist

• A market can be created with 2–N outcomes and resolves to exactly one.
• Payout to winners is pro-rata and conserves the total pool.
• Creation reverts if outcomes exceed the configured maximum.
• Tests cover 3-way and N-way markets end to end.

Related Files

• config.rs
• market.rs
• prediction.rs
• storage_types.rs
• lib.rs
• market_tests.rs

Resolves #1329

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Project	Deployment	Actions	Updated (UTC)
insight-arena-4rll	Ready	Preview, Comment	Jul 28, 2026 4:59pm

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[Olowodarey]

@AJ0070 pls fix CI

[AJ0070]

@Olowodarey Can you please trigger the CI tests again?

[AJ0070]

@Olowodarey Are there any other issues which I can take up?