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,