Improving Implement buffered document importing for improved performance

[tnaum-ms]

Closes #130
Fixes #136

[Copilot]

Pull Request Overview

This PR adds a buffering layer for batched document inserts to improve performance and updates import logic to leverage that buffer, while also enhancing error handling and progress reporting.

• Introduces DocumentBuffer with configurable thresholds and a factory for MongoDB defaults.
• Extends ClustersClient to handle unordered bulk writes and log detailed write errors.
• Refactors importDocuments to use the buffer for bulk inserts, adjust progress increments, and localize final messages.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/utils/documentBuffer.ts	Adds new DocumentBuffer class and createMongoDbBuffer utility for batched writes.
src/documentdb/ClustersClient.ts	Wraps insertMany in try/catch, logs bulk write errors.
src/commands/importDocuments/importDocuments.ts	Refactors import flow to use buffering, updates progress reporting and error accumulation.
l10n/bundle.l10n.json	Updates localized strings for new final messages and write errors.

Comments suppressed due to low confidence (3)

src/utils/documentBuffer.ts:93

• Add unit tests for DocumentBuffer to cover insertion, flushing, and error scenarios (e.g., oversized documents, empty documents).

export class DocumentBuffer<T> {

src/utils/documentBuffer.ts:138

• [nitpick] documentsToProcess is undefined on success but an array in other cases; consider always returning an array (empty on success) for consistency and simpler downstream handling.

            return { ...insertResult, documentsToProcess: undefined };

src/documentdb/ClustersClient.ts:496

• Calling ext.outputChannel.show() inside the loop can trigger the UI repeatedly; move this call after logging all write errors to show the output channel only once.

                    ext.outputChannel.show();