docs: fold voice dictation notes into the dependency list

No other feature gets its own README section; the install doc is a
dependency list and keybindings live in the cheatsheet. The detailed
setup notes live in the knowledge base, so the README only keeps the
short parentheticals a fresh install actually needs.

README.md

@@ -109,37 +109,15 @@ You also need to install all the dependencies:
 - fcitx5-hangul
 - pipewire-alsa (whisrs captures audio via raw ALSA; without it the default
   PCM is the headset-jack mic, which is silent when nothing is plugged in)
-- vulkan-intel and vulkan-icd-loader (iGPU decode; already standard on systems
+- vulkan-intel and vulkan-icd-loader (already standard on systems
   with Intel graphics set up for Vulkan)
-- whisrs-git (AUR; voice dictation daemon, see below)
+- whisrs-git (AUR; hold-to-talk voice dictation on the Copilot key. The stock
+  AUR build is too slow for dictation: rebuild locally with -march=native and
+  the vulkan cargo feature, see ~/Projects/whisrs-local-build)
 
 There are probably more, I will update the list next time I'm
 installing it on a new computer.
 
-Voice dictation
-===============
-
-The Copilot key (on newer laptops this replaced the right Ctrl key; it
-sends SUPER+SHIFT+F23) toggles voice dictation. Hold it to record and
-release to transcribe: one whisrs toggle fires on press, another on
-release. whisrs transcribes locally with a whisper.cpp model and types
-the text at the cursor in any window, including terminals running the
-dockerized agent harnesses. Text injection uses the Wayland
-virtual-keyboard protocol on Hyprland, with a uinput fallback that the
-package's udev rule grants access to.
-
-The config lives in ~/.config/whisrs/config.toml (set [audio] device =
-"pipewire" so capture goes through PipeWire) and the model in
-~/.local/share/whisrs/models/. The daemon runs as the systemd user
-service whisrs.service.
-
-The stock AUR build decodes on the CPU with generic -march flags, which
-makes dictation take around five seconds. On this machine the package
-is rebuilt locally with -march=native plus the vulkan cargo feature so
-decoding runs on the Intel iGPU instead; that drops latency to roughly
-a second. After AUR updates, re-apply via
-~/Projects/whisrs-local-build/build.sh.
-
 License
 =======