…#253)

Create a common interface and pattern for HTTP transport configuration to
enable code sharing between SSEServer and the upcoming StreamableHTTPServer.

- Add new httpTransportConfigurable interface for shared configuration
- Refactor SSEServer to implement the shared interface
- Convert With* option functions to work with both server types
- Add stub for StreamableHTTPServer to demonstrate implementation pattern
- Deprecate WithSSEContextFunc in favor of WithHTTPContextFunc

This change preserves backward compatibility while allowing the reuse of
configuration code across different HTTP server implementations.

This commit adds a new CI job that runs code generation and verifies no 
uncommitted changes exist. This prevents accidental manual edits to 
autogenerated files by:

1. Running `go generate ./...` during CI
2. Failing the build when generated code differs from committed code
3. Providing clear error messages with instructions for developers

* Fix the issue where the 'Shutdown' method fails to properly exit.

* Fix the issue where the 'Shutdown' method fails to properly exit.

---------

Co-authored-by: CHENBING1 <chenbing1@kingsoft.com>

)

This test demonstrates the deadlock described in
#254 and
#263 by running
`SSEServer.Start` then `SSEServer.Shutdown`. If it deadlocks, the test
fails quickly and reliably, rather than hanging indefinitely.

References:

- #254
- #255
- #263

…ot exists (#266)

…Line() (#257)