Initial commit: wireframe packet capture/analysis tool

Terminal packet capture and analysis tool built to learn the C++
memory model (byte layout, alignment, endianness, std::span over
unowned buffers) via a real capture pipeline.

- Hand-rolled L2-L4 decoders (Ethernet, IPv4, IPv6 with extension
  header walking, TCP, UDP) over std::span, no struct-casting
- L7 dissector interface with DNS, HTTP, and TLS SNI implementations
- pcapng read/write for Wireshark-compatible capture files
- Bounded capture queue: drop-on-backpressure for live capture,
  blocking push for faithful file replay
- Kernel-level BPF filtering (-f) and a separate display-only search
  (-g / interactive) that doesn't touch what's captured
- Replay mode (-r) reads a saved pcapng file back through the same
  pipeline as live capture, no root or live device needed
- pcap_stats() surfaces kernel/interface drops invisible to the
  capture queue's own counter
- Three frontends sharing one CaptureSession setup path: CLI, TUI
  (FTXUI, primary), GUI (Dear ImGui + SDL3, secondary)
- 89 unit tests (doctest) plus 9 libFuzzer harnesses covering every
  hand-rolled parser; fuzzing found and fixed a real OOM in the
  pcapng reader (unbounded allocation from an untrusted length field)

1 files changed, 22 insertions, 0 deletions

diff --git a/include/wireframe/byteio.hpp b/include/wireframe/byteio.hpp
new file mode 100644
index 0000000..c37c29e
--- /dev/null
+++ b/include/wireframe/byteio.hpp
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <cstdint>
+#include <span>
+
+// Manual big-endian reads instead of reinterpret_cast onto a packed
+// struct: network buffers from pcap aren't guaranteed aligned for
+// multi-byte integer types, so casting would be undefined behavior.
+namespace wireframe {
+
+inline std::uint16_t read_be16(std::span<const unsigned char> bytes, std::size_t offset) {
+    return static_cast<std::uint16_t>((bytes[offset] << 8) | bytes[offset + 1]);
+}
+
+inline std::uint32_t read_be32(std::span<const unsigned char> bytes, std::size_t offset) {
+    return (static_cast<std::uint32_t>(bytes[offset]) << 24) |
+           (static_cast<std::uint32_t>(bytes[offset + 1]) << 16) |
+           (static_cast<std::uint32_t>(bytes[offset + 2]) << 8) |
+           static_cast<std::uint32_t>(bytes[offset + 3]);
+}
+
+}  // namespace wireframe