docs: record the first live HID cable proof

docs/tasks/62-full-usb-kvm.md

@@ -43,6 +43,12 @@ the system D-Bus mechanism.
 The separate local `souveraine-usb` repo is a safety copy from the first
 layout attempt, not a source of record. Do not build another package from it.
 
+The HID branch deliberately separates the mechanism from its eventual human
+surface. `USB control link` composes or releases the keyboard, pointer and NCM
+functions. `Keyboard & trackpad` is the doorway reserved for a compact
+controller app: popup keyboard, trackpad and a few guarded quick actions. The
+power sheet does not pretend those app controls exist before that surface does.
+
 ## Verification already earned
 
 - Receiver unit tests: RGB565 dirty-rect conversion and HID usage mapping.
@@ -145,6 +151,16 @@ Still true from the pre-landing inspection:
 The shell's KVM button is now enabled by live feature discovery, not a version
 guess.
 
+### First HID cable proof — 2026-08-07
+
+With `USB HID Injection` selected, the device controller reported
+`state=configured`; `/run/souveraine-usb/{keyboard,pointer}` resolved to the
+live `/dev/hidg0` and `/dev/hidg1` endpoints. From the unprivileged phone
+session, `usb-hid-inject type` wrote `Rook was here. The wire has hands.` into
+the focused host field exactly. That closes host enumeration and keyboard
+report delivery. Pointer report delivery and the return to developer USB are
+still owed before landing-order step 3 is complete.
+
 ## Landing order
 
 1. **Done.** Publish/install the new `souveraine`, `smoo`, and