Add a batch contribution read view returning many investors' funded amounts in one call

[mikewheeleer]

Add a batch contribution read view returning many investors' funded amounts in one call

Description

get_contribution(investor) returns a single investor's funded principal, and get_investors(start, limit) paginates addresses. To render a cap table, an integrator must call get_contribution once per address — N round-trips for N investors. There is no way to fetch a page of (address, amount) pairs together, which is wasteful for indexers reconstructing the book.

This issue adds get_contributions(addresses: Vec<Address>) -> Vec<i128> that resolves each supplied address to its recorded contribution (zero for non-funders) in a single read call, mirroring the input order.

Requirements and context

• Repository scope: Liquifact/Liquifact-contracts only.
• Add get_contributions(addresses: Vec<Address>) -> Vec<i128> returning one amount per input address, in order, reusing the same storage path as get_contribution.
• Return 0 for any address with no recorded contribution (never panic on unknown addresses).
• Bound the input length with a constant (e.g. reuse the existing pagination ceiling) and reject oversized batches with a typed error to avoid unbounded reads.
• Pure read-only: no auth, no writes, no TTL bump.

Suggested execution

• Fork the repo and create a branch
• git checkout -b feature/contracts-batch-contribution-view
• Implement changes
  • Write code in: escrow/src/lib.rs — get_contributions.
  • Write comprehensive tests in: escrow/src/tests/funding.rs — assert order preservation, zero for unknown addresses, equivalence with per-address get_contribution, the empty-input case, and the over-cap rejection.
  • Add documentation: extend the integrator view-surface reference with the batch read.
  • Include NatSpec-style doc comments (///) on the new view.
  • Validate security assumptions: bounded reads, no mutation, no panic on unknown input.
• Test and commit

Test and commit

• Run cargo fmt --all -- --check, cargo build, and cargo test.
• Cover edge cases and failure paths: empty vector, mix of funders and non-funders, duplicate addresses, batch at and above the cap.
• Include the full cargo test output and a short security notes section in the PR description.

Example commit message

feat: add bounded batch contribution read view with order and equivalence tests

Guidelines

• Minimum 95 percent test coverage for impacted modules.
• Clear, reviewer-focused documentation.
• Timeframe: 96 hours.

Community & contribution rewards

• 💬 Join the Liquifact community on Discord for questions, reviews, and faster merges: https://discord.gg/JrGPH4V3
• ⭐ This is a GrantFox OSS / Official Campaign task and may be rewarded. When your PR is merged you'll be prompted to rate the project — if this issue and the maintainers helped you ship, we'd be grateful for a 5-star rating. Clear questions in Discord and tidy, well-tested PRs are the fastest path to a merge and a reward.