fix(tholos-v2): emit Revealed events on auto-reveal path (#156)

[s6pa1rta3n-lab]

Summary

In tholos-v2, the Registration -> Reveal phase transition occurs lazily upon the first reveal or resolve_outcome call after the registration deadline. Fixed positions (asserter and disputer) have their position weights auto-counted into agree_weight and disagree_weight, but previously did not emit corresponding Revealed events.

This PR fixes #156 by emitting Revealed events for each fixed position inside open_reveal_phase, ensuring downstream indexers observe a consistent and complete sequence of position reveals without needing special handling for fixed positions.

Changes

• Emitted Revealed { id, voter, choice } for both fixed voters inside open_reveal_phase in contracts/tholos-v2/src/lib.rs.
• Preserved existing RevealOpened event emission order and phase transition state logic.
• Added comprehensive unit tests in contracts/tholos-v2/src/test.rs verifying event emissions and choice mappings for both outcome == true and outcome == false assertions.
• Updated events table in docs/src/CONTRACT_V2.md and added an entry to docs/src/CHANGELOG.md.

Verification

• cargo fmt --check: passed
• cargo clippy --workspace --all-targets -- -D warnings: passed
• cargo test --workspace: 185 passed across all workspace crates

Payout Routing

• EVM (Base/Arbitrum/Polygon/ETH): 0xF46C9F6d70C50BF81ef3588AB523a90a594a2F89
• Stellar: GCL6OXAMLD75BMTINA6EMRUDWK5THQUSHMYNLSNBCJAPZJHNYJTUNIBC

[collinsezedike]

@s6pa1rta3n-lab Closing. #156 has no assignee. Comment on the issue and wait to be assigned before opening a PR.