feat: manage Handy preferences and startup declaratively

docs/constellation-work.md

@@ -119,40 +119,29 @@ reports are not a fresh comparison with this baseline.
 ## Open choices and next discussion
 
 Dictation: plain local transcription is selected; rambling cleanup is deferred.
-The shared Niri module installs Handy and starts it hidden with the desktop.
-Super+D toggles recording; Super+Shift+D cancels. Commands were verified against
-the pinned Handy 0.9.1 source. No microphone recording or model download was run.
-After user activation, launch Handy from Walker, download/select Parakeet V3,
-keep automatic language detection and disable push-to-talk for toggle operation.
-In Advanced, choose paste method None and clipboard handling Copy to Clipboard.
-Keep post-processing disabled. Settings/models remain writable app-owned state.
-Start Handy manually for the current session; desktop autostart applies on login.
-Try an English and a Dutch recording, paste into Codex with Ctrl+Shift+V, then
-submit manually. User feedback needed: recognition accuracy, delay and shortcut
-delivery. Automatic paste can follow if wanted after checking Niri compatibility.
-Verification: formatting, flake evaluation, Zenith and Polaris no-link system
-builds, and whitespace checks passed. No system activation or interactive
-dictation was performed; recognition quality and latency remain unmeasured.
-First-use diagnosis: Handy was set to Nemotron, Direct Input, Don't Modify
-Clipboard and push-to-talk. One recording transcribed but output used X11 input
-simulation; other recordings returned zero usable samples. Default digital mic
-is unmuted. Set None + Copy to Clipboard and retry a full sentence; microphone
-selection/voice detection needs further checking if History stays empty.
-Niri Super+D invokes a forced toggle, independent of Handy's push-to-talk setting;
-Handy's Ctrl+Space global binding is not the Niri binding. Keep the user's minimal
-overlay. Noctalia's native microphone filter suppresses all microphone activity
-popups/indicators, while camera and screen-sharing indications remain enabled.
-The Noctalia change passed formatting, flake evaluation and both workstation
-builds; user activation and the clipboard retry remain pending.
-Automatic paste: Niri now includes wtype, which Handy natively uses to deliver
-Wayland paste shortcuts. Set Paste Method to Ctrl+Shift+V for Kitty, keep automatic
-submission off, and restart Handy after activation. Interactive delivery remains
-unverified. Handy 0.9.1 supports Overlay Style Live with streaming models; the
-selected Nemotron Streaming 3.5 is a suitable candidate. Minimal hides live text.
-This supersedes the initial Parakeet V3/clipboard-only recommendation when live
-feedback and automatic paste are wanted; no custom input script is needed.
-The wtype addition passed formatting, flake evaluation, both workstation builds
-and whitespace checking. Activation and the interactive paste trial are pending.
+Handy preferences are Nix-owned in `modules/capabilities/handy.nix`: Nemotron
+Streaming 3.5, automatic language detection, default microphone, Live overlay at
+the bottom, Ctrl+Shift+V paste through wtype, preserved clipboard, manual submission
+and no cloud processing. Other preferences use pinned app defaults. A user service
+copies the baseline into Handy's writable store on each start, allowing migrations
+while resetting GUI edits. Models/recordings stay outside Nix; the selected model
+is already downloaded on Zenith. Other hosts still need model provisioning.
+Super+Shift+D toggles; Super+Ctrl+D cancels. Super+D push-to-talk awaits the user's
+decision about a keyboard listener: Niri 26.04 has no key-release bindings.
+Noctalia suppresses microphone activity popups/indicators; camera and screen-sharing
+indications remain. Automatic paste and live capture need interactive checks.
+
+Hang investigation: stopping live Vulkan transcription never completed; cancel
+returned the UI to idle but subsequent requests reported pipeline busy. Handy was
+no longer running when inspected; no crash cause is established. The same saved
+1.56-second recording completed in CPU batch mode (135 ms inference, 729 ms load)
+and Vulkan batch mode (156 ms inference, 420 ms load). This checks model inference,
+not live capture/stop/cancel. No new audio was recorded. Switching to CPU is not a
+confirmed fix. After activation, retry live recording and stopping, and inspect
+the service logs if it hangs.
+Verification: formatting, flake evaluation, both workstation builds and whitespace
+checks passed. Handy loaded the generated settings in an isolated data directory
+without settings parse errors. System activation remains user-owned and pending.
 
 The focus is the broader environment, not further API/database polish. Candidate
 areas remain places/ownership, navigation/interaction, human/agent collaboration,

docs/constellation.md

@@ -29,8 +29,8 @@ use a flake to declare its tools without Nix owning the surrounding workspace.
   interaction with useful connections to the rest of the environment.
 - Use Handy for local plain dictation, mainly English with occasional Dutch.
   Use native Wayland automatic paste and optional live text with a streaming model.
-  Niri owns recording shortcuts;
-  model downloads and microphone preferences remain application-owned. Cleanup
+  Nix owns Handy preferences and desktop integration; the user service restores
+  settings on each start. Model downloads and recordings remain application data. Cleanup
   through Codex, a cloud API or a local language model is deferred.
 - Outlook is acceptable as an application, but its interaction and integration
   do not fit as naturally. Accessible mail for tools and agents matters separately

modules/capabilities/handy.nix

@@ -0,0 +1,46 @@
+{
+  flake.modules.homeManager.handy =
+    { config, pkgs, ... }:
+    let
+      settings = (pkgs.formats.json { }).generate "handy-settings.json" {
+        settings = {
+          settings_schema_version = 1;
+          selected_model = "handy-computer/nemotron-3.5-asr-streaming-0.6b-gguf/nemotron-3.5-asr-streaming-0.6b-Q8_0.gguf";
+          selected_language = "auto";
+          translate_to_english = false;
+          selected_microphone = null;
+          always_on_microphone = false;
+          push_to_talk = true;
+          paste_method = "ctrl_shift_v";
+          typing_tool = "wtype";
+          clipboard_handling = "dont_modify";
+          auto_submit = false;
+          overlay_style = "live";
+          overlay_position = "bottom";
+          post_process_enabled = false;
+          start_hidden = true;
+          autostart_enabled = false;
+          update_checks_enabled = false;
+          show_whats_new_on_update = false;
+          onboarding_completed = true;
+        };
+      };
+    in
+    {
+      home.packages = [ pkgs.handy ];
+
+      systemd.user.services.handy = {
+        Unit = {
+          Description = "Handy dictation";
+          PartOf = [ "graphical-session.target" ];
+          After = [ "graphical-session.target" ];
+        };
+        Install.WantedBy = [ "graphical-session.target" ];
+        Service = {
+          # Handy writes migrations and runtime preferences: restore the Nix baseline on start.
+          ExecStartPre = "${pkgs.coreutils}/bin/install -Dm600 ${settings} ${config.xdg.dataHome}/com.pais.handy/settings_store.json";
+          ExecStart = "${pkgs.handy}/bin/handy --start-hidden";
+        };
+      };
+    };
+}

modules/capabilities/niri/_bindings.nix

@@ -36,7 +36,7 @@ in
   };
 
   # Dictation
-  "Mod+D" = {
+  "Mod+Shift+D" = {
     spawn = [
       handy
       "--toggle-transcription"
@@ -44,7 +44,7 @@ in
     _props.repeat = false;
     _props.hotkey-overlay-title = "Toggle Dictation";
   };
-  "Mod+Shift+D" = {
+  "Mod+Ctrl+D" = {
     spawn = [
       handy
       "--cancel"

modules/capabilities/niri/default.nix

@@ -41,19 +41,11 @@ in
             playerctl
             brightnessctl
             wireplumber
-            handy
             wtype
           ]
           ++ [ swapMonitorWorkspaces ];
       };
 
-      desktop.autostart = [
-        [
-          (lib.getExe pkgs.handy)
-          "--start-hidden"
-        ]
-      ];
-
       dconf.settings."org/gnome/desktop/interface".color-scheme = "prefer-dark";
 
       wayland.windowManager.niri = {

modules/profiles/workstation-base.nix

@@ -43,6 +43,7 @@ in
     imports = [
       homeModules.passwords
       homeModules.clipboard
+      homeModules.handy
       homeModules.desktop-commands
       homeModules.dev-tools
       homeModules.xdg