chore(sds): optimise lookups

[danisharora099]

Description

The current ILocalHistory implementation behaves like an array (push, find, some, slice), which forces repeated linear scans when checking message dependencies. This results in an O(N × M) complexity for dependency resolution and causes performance degradation as history size grows.

While the behavior is functionally correct, the architecture is inefficient for large or frequently accessed histories. A domain-specific API is needed to support efficient lookups and scalable dependency checks.

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User Story

• As a developer, I want ILocalHistory to support efficient message lookups and dependency checks, so that SDS can perform reliably at scale without incurring unnecessary computation.
• As a system integrator, I want predictable and performant history operations, so growing message histories do not negatively impact runtime.

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Proposed Solution / Feature Design

Refactor ILocalHistory to use a domain-specific interface backed by a hashmap that enables O(1) message lookups.

New Interface

export interface ILocalHistory {
  readonly size: number;
  addMessages(...messages: ContentMessage[]): void;
  hasMessage(messageId: string): boolean;
  getMessage(messageId: string): ContentMessage | undefined;
  getRecentMessages(count: number): ContentMessage[];
  getAllMessages(): ContentMessage[];
  findMissingDependencies(entries: HistoryEntry[]): HistoryEntry[];
}

Key Design Changes

• Remove generic array-like behaviors (push, find, some, slice).
• Introduce clear, purpose-built history methods.
• Use a messageIndex hashmap internally for O(1) lookup times.
• Improve dependency resolution complexity from O(N × M) to O(N + M)

Notes

• Helps ensure SDS recovery and message processing remain efficient as history grows.