Initial import: ESP32 ZiFi32 firmware with SMB2/3 VFS bridge

Based on https://github.com/tslabs/zx-evo/tree/master/pentevo/esp32,
extended with an SMB2/3 server that exposes the ZX Evolution's real SD
card as a network share (browse/download/upload/delete), plus assorted
stability and protocol-correctness fixes in vfs_bridge.cpp and the
vendored libsmb2 - see firmware/README.md for the detailed changelog
and current status.

Also adds:
- firmware/: ready-to-flash compiled binaries + flashing instructions
- hardware/: adapter board connection diagram, PCB photo, and Gerber
  files
- src/third_party/libsmb2: vendored from sahlberg/libsmb2 (LGPL-2.1,
  see its own COPYING/LICENCE files), de-submoduled to a plain
  snapshot with local patches applied directly

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/main/idf_component.yml

@@ -0,0 +1,18 @@
+## IDF Component Manager Manifest File
+dependencies:
+  ## Required IDF version
+  idf:
+    version: '>=4.1.0'
+  # # Put list of dependencies here
+  # # For components maintained by Espressif:
+  # component: "~1.0.0"
+  # # For 3rd party components:
+  # username/component: ">=1.0.0,<2.0.0"
+  # username2/component2:
+  #   version: "~1.0.0"
+  #   # For transient dependencies `public` flag can be set.
+  #   # `public` flag doesn't have an effect dependencies of the `main` component.
+  #   # All dependencies of `main` are public by default.
+  #   public: true
+  espressif/usb_host_hid: ^1.1.0
+  espressif/esp_new_jpeg: ^1.0.0