feat: keep internal error in worker's quit reason

[4t145]

fix #345

Motivation and Context

How Has This Been Tested?

Breaking Changes

1. Change the error type for local session worker.
2. Change the type defination of worker's QuitReason
3. Fix some typo of StreamableHttpError

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[Copilot]

Pull Request Overview

This PR enhances error handling in the transport worker system by making the WorkerQuitReason generic over error types, allowing workers to preserve their specific error types rather than converting them to strings. It also fixes spelling errors in StreamableHttpError variants.

Key changes:

• Made WorkerQuitReason generic over error types to preserve internal error information
• Updated all worker implementations to use specific error types instead of generic string errors
• Fixed typos in StreamableHttpError enum variants (Sever → Server)

Reviewed Changes

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

File	Description
crates/rmcp/src/transport/worker.rs	Made WorkerQuitReason generic over error type E and updated method signatures
crates/rmcp/src/transport/streamable_http_server/session/local.rs	Introduced LocalSessionWorkerError enum and updated worker implementation to use specific error types
crates/rmcp/src/transport/streamable_http_client.rs	Fixed spelling errors and updated to use generic error types in method calls
crates/rmcp/src/transport/common/reqwest/streamable_http_client.rs	Fixed spelling error in error variant name

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[jokemanfire]

LGTM

[4t145]

Just adopted copilot's suggestion.