fix: optimize queue lookup with mapping-based O(1) duplicate detection (#45)

[RonTuretzky]

Summary

• Replace O(n) linear search with O(1) mapping-based duplicate detection for both addition and removal queues
• Add MAX_QUEUE_SIZE = 100 constant to bound gas consumption of clearAdditionQueue/clearRemovalQueue
• Add MaxQueueSizeReached error to IRecipientRegistry
• Both queue mappings use EIP-7201 namespaced storage (inside existing struct)

Closes #45
Supersedes #90 (addresses all review feedback from that PR)

Test plan

• Re-queue after removal works correctly
• Re-queue after clearing addition queue works correctly
• Double-queue reverts with RecipientAlreadyQueued
• Addition and removal queues are independent
• MAX_QUEUE_SIZE enforced on both queues
• All 103 existing tests pass

Stack: PR 1 of 10 (0.0.1)

[Copilot]

Pull request overview

This PR optimizes recipient addition/removal queue duplicate detection by switching from linear scans to mapping-backed O(1) membership checks, and introduces a queue-size cap intended to keep queue-clearing gas bounded.

Changes:

• Add isQueuedForAdditionMapping / isQueuedForRemovalMapping to enable O(1) duplicate detection and isQueuedFor* lookups.
• Enforce MAX_QUEUE_SIZE = 100 for both addition and removal queues, reverting with a new MaxQueueSizeReached error.
• Expand registry tests around re-queuing behavior and tighten revert expectations for duplicate queueing.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
src/abstract/AbstractRecipientRegistry.sol	Adds queue membership mappings, enforces max queue size, and updates clearing logic to reset mapping state.
src/interfaces/IRecipientRegistry.sol	Introduces MaxQueueSizeReached error for queue cap enforcement.
test/RecipientRegistry.t.sol	Adds re-queueing and queue-independence tests; updates duplicate-queue revert assertions to check RecipientAlreadyQueued.

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