…lers

- Fix all migration.md examples to use ServerRequestContext instead of RequestContext
- Fix all imports to use 'from mcp.server import Server, ServerRequestContext'
- Apply ruff formatting to code examples
- Add Server constructor calls to examples that were missing them
- Re-export ServerRequestContext from mcp.server.__init__
- Add type hints to TaskResultHandler docstring example

…erver

Move handler functions from a dict-returning method to private methods
on MCPServer, passed directly to the Server constructor by name. This
eliminates the **kwargs unpacking pattern and makes the handler
registration explicit.

Allow users to override default task handlers by passing on_get_task,
on_task_result, on_list_tasks, and on_cancel_task to enable_tasks().
User-provided handlers are registered first; defaults fill in the rest.

…tT default

The subscribe capability in ResourcesCapability was hardcoded to False,
even when on_subscribe_resource handler was provided. Now dynamically
checks whether a subscribe handler is registered.

Also applies ruff formatting to experimental.py.

Convert the 3 remaining experimental task server test files:
- test_integration.py: proper lifespan + Client pattern
- test_run_task_flow.py: constructor kwargs + Client pattern
- test_server.py: enable_tasks() kwargs + Client pattern

All tests use proper typing with ServerRequestContext and
constructor kwargs instead of decorators.

- Delete test_func_inspection.py (tested removed create_call_wrapper)
- Delete test_lowlevel_input_validation.py and test_lowlevel_output_validation.py
  (tested jsonschema validation removed from low-level server)
- Migrate test_read_resource.py to E2E with Client
- Migrate test_129_resource_templates.py to E2E with Client
- Migrate test_output_schema_validation.py to constructor kwargs
  (removed bypass_server_output_validation hack, no longer needed)
- Migrate test_ws.py, test_sse.py, test_streamable_http.py from Server
  subclasses with decorators to standalone handlers with constructor kwargs
- Replace self.request_context contextvar with ctx parameter
- Replace global _server_lock with typed ServerState lifespan context
- Fix import paths for TextContent, ClientRegistrationOptions,
  RevocationOptions, StreamableHTTPServerTransport

enable_tasks registers default handlers for all task methods, so
partial capabilities aren't currently possible. Skipped tests with
TODO(maxisbey) to revisit when low-level API supports selectively
enabling/disabling individual task capabilities.

…attern

- Convert all low-level Server examples from decorator-based handlers
  to constructor on_* kwargs pattern
- Replace server.request_context with ctx parameter passed to handlers
- Replace auto-wrapped return values (dict, str, bytes) with explicit
  result type construction (CallToolResult, ReadResourceResult, etc.)
- Update everything-server to use _add_request_handler for subscribe/
  unsubscribe/logging handlers (MCPServer doesn't expose these yet)
- Update migration docs with detailed section on removed auto-wrapping
- Update README snippets

Remove references to automatic content/structured conversion and
the four return type options that no longer exist. Low-level handlers
now always return CallToolResult directly.

- Remove unused _add_notification_handler from Server
- Add pragma no cover for dead dict code path in MCPServer._handle_call_tool
- Add E2E test for MCPServer.completion() decorator
- Replace unused handle_list_tools stubs with raise NotImplementedError
- Add pragma no cover for skipped tests in test_server and test_spec_compliance
- Flatten nested completion handler logic to eliminate untaken branches
- Fix test_88_random_error to use assert + shared return path
- Clean up unused imports (Tool, ToolExecution, TASK_REQUIRED)

…test