[Ranjeet2063]

Description

Closes #314

Resolves fund-stranding for tasks that resolve successfully but whose vault release fails. Previously, try_release_vault_funds swallowed vault failures by emitting an event, but because the task was marked is_done = true, the release block guarded by !t.is_done could never execute again, stranding contributor payouts permanently on-chain.

This PR introduces:

1. Persistent recording of failed releases in contract storage under DataKey::PendingRelease(task_id) and DataKey::AllPendingReleases.
2. A permissionless retry_vault_release(task_id) entrypoint guarded against reentrancy and paused states, which attempts the release again, clears the pending record on success, and prevents double-releasing.
3. A public read entrypoint get_pending_releases() to query all outstanding unreleased task IDs without replaying past events.
4. Clean compaction of pending release state if a terminal task is purged via purge_task.

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Key Changes

1. Storage Layout (src/contracts/storage_layout.rs, src/storage.rs)

• Added DataKey::PendingRelease(u64) namespace key and DataKey::AllPendingReleases index key.
• Added helper functions:
  • has_pending_release(env, task_id) -> bool
  • get_pending_releases(env) -> Vec<u64>
  • set_pending_release(env, task_id) (appends to AllPendingReleases if not already tracked)
  • remove_pending_release(env, task_id) (removes key and compacts AllPendingReleases)

2. Error Definition & Gas Accounting (src/types.rs, src/gas.rs)

• Added error variant ContractError::NoPendingRelease = 43.
• Added operation Operation::RetryVaultRelease = 30 and registered calibrated gas estimate COST_RETRY_VAULT_RELEASE = 3_000_000.

3. Voting & Recovery Implementation (src/contracts/voting.rs, src/contracts/logic.rs)

• In try_release_vault_funds: On Err(_), records storage::set_pending_release(env, task_id) while maintaining non-reverting resolution fault isolation.
• Implemented retry_vault_release(env, task_id):
  • Validates task ID and checks that the contract is not paused.
  • Verifies has_pending_release; returns Err(ContractError::NoPendingRelease) if not pending.
  • Acquires reentrancy lock.
  • Invokes VaultClient::try_release_funds.
  • On success: clears pending release record, emits vault_ok event, releases reentrancy lock.
  • On failure: preserves pending record for future retry, emits vault_err event, releases reentrancy lock, and returns Err(ContractError::EscrowUnavailable).

4. Entrypoint Surface (src/contracts/proxy_entry/entry_tasks.rs)

• Exposed public write entrypoint pub fn retry_vault_release(env: Env, task_id: u64) -> Result<(), ContractError>.
• Exposed public read entrypoint pub fn get_pending_releases(env: Env) -> Vec<u64>.

5. Task Purge Compaction (src/task.rs)

• In purge_task: cleans up any pending release storage and index entries for terminal tasks.

6. Test Suite (tests/vault_release_retry.rs)

• Added 9 comprehensive integration tests covering all Acceptance Criteria:
  1. test_task_resolves_and_records_pending_release_when_vault_fails: Task resolves even if vault fails, and task is recorded in get_pending_releases().
  2. test_successful_vault_release_does_not_create_pending_release: Happy path releases directly without creating pending record.
  3. test_retry_after_vault_recovers_releases_funds_and_clears_record: Vault recovery enables successful retry which clears the pending record.
  4. test_retry_for_task_with_no_pending_release_is_rejected: Non-pending tasks reject retry with NoPendingRelease.
  5. test_retrying_twice_does_not_double_release: Second retry attempt rejects with NoPendingRelease.
  6. test_retry_fails_when_vault_still_unhealthy_preserves_record: Unhealthy vault failure preserves pending record.
  7. test_purging_task_cleans_up_pending_release: Task purging clears pending release state.
  8. test_retry_vault_release_paused_rejected: Paused contract rejects retry.
  9. test_batch_voting_records_pending_release_on_failure: Batch voting correctly records multiple failed releases.

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Acceptance Criteria Checklist

• A task whose vault release fails still resolves (the Vault release_funds call is not fault-isolated — a broken vault can permanently block task resolution #134 / fix: isolate vault release_funds call to prevent task resolution DoS #184 behaviour is preserved unchanged)
• That task is recorded as having an outstanding release
• A retry after the vault recovers releases the funds and clears the record
• A retry for a task with no pending release is rejected
• Retrying twice does not double-release

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[Ranjeet2063]

Hello @maintainers,

Just a quick note that all local unit and integration tests are passing cleanly across the test suite (cargo test). Could maintainers please trigger / approve the CI workflow run on this pull request when convenient? Thank you!