Implement libbpf synchronous ring buffer API

[mikeagun]

Description

Implements libbpf synchronous API (poll/consume) for ring buffer map.

Closes #3633

Testing

Adds tests to api_test.cpp and libbpf_test.cpp covering new ring buffer map API and the libbpf ring buffer manager.

Documentation

Updates docs/RingBuffer.md to match the updated API.

Installation

N/A

[Copilot]

Pull request overview

This PR implements the libbpf synchronous ring buffer API (poll/consume) for Windows, bringing it closer to Linux compatibility. The default behavior now uses synchronous callbacks (matching Linux), while asynchronous callbacks are available via a Windows-specific flag.

Key Changes:

• Added ring_buffer__poll() and ring_buffer__consume() functions with Linux-compatible behavior
• Implemented synchronous mode using memory-mapped ring buffer access with event-based notifications
• Updated ring_buffer structures to support both synchronous and asynchronous modes
• Fixed error code handling to return negative errno values consistently with libbpf conventions

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
libs/api/libbpf_map.cpp	Core implementation of synchronous ring buffer APIs with memory mapping and event handling
include/ebpf_api.h	Added public API definitions for ring buffer consumer/producer page structures and new functions
include/bpf/libbpf.h	Added Linux-compatible ring buffer API declarations (poll, consume, add)
libs/api/api_internal.h	Added forward declaration for ring_buffer_sample_fn callback type
libs/runtime/ebpf_ring_buffer.h	Moved ring buffer page type definitions to public API header
tests/unit/libbpf_test.cpp	Comprehensive tests for Linux-compatible and Windows-specific ring buffer APIs
tests/api_test/api_test.cpp	End-to-end tests for synchronous ring buffer with real eBPF programs
tests/end_to_end/end_to_end.cpp	Fixed error checking to expect negative errno values from libbpf_get_error
libs/runtime/unit/platform_unit_test.cpp	Removed verbose console output from ring buffer stress tests
docs/RingBuffer.md	Updated documentation to reflect synchronous API implementation and usage patterns
ebpfapi/Source.def	Added exports for new ring buffer functions

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[Copilot]

The CreateEvent call uses FALSE for the bManualReset parameter, creating an auto-reset event. However, this may cause a race condition in the ring buffer polling logic. When ring_buffer__poll is called, it first does a non-blocking wait with timeout 0 (line 668) to clear the event, then calls ring_buffer__consume (line 671), and only then waits on the handle if no data is available (line 682). If a producer writes data between the initial clear (line 668) and the wait (line 682), the event could be set and then immediately auto-reset by the OS when checked, causing the consumer to miss the notification and potentially wait unnecessarily. Consider using a manual-reset event (TRUE for bManualReset) and explicitly resetting it after consuming data to avoid this race condition.

Suggested change

	HANDLE wait_handle = CreateEvent(nullptr, FALSE, FALSE, nullptr);
	HANDLE wait_handle = CreateEvent(nullptr, TRUE, FALSE, nullptr);