agent: dogfood polish 2026/04/19 — Linux native chrome + History redesign + mic picker cleanup

Second dogfood sprint. Headline fix: Linux now uses native KWin/Mutter
decorations instead of fragile frameless `startResizeDragging`, which
collapsed diagonal corner resize to a single axis and made drag feel
laggy. macOS / Windows keep custom chrome via `useCustomChrome` gate.

Other changes:

- Cross-window preferences sync via `kon:preferences-changed` Tauri
  event — theme and font changes propagate live to float/viewer.
- Hotkey recorder rewritten to use capture-phase document listener
  gated by $effect; button focus was unreliable in webkit2gtk.
- History page redesigned for cognitive-load hygiene: title-first
  compact row, inline title input, Edit popout opening /viewer in
  edit mode, clipboard export as .md with YAML frontmatter, manual
  tag chips + + Add tag input, header tag filter (cap 7), global
  Starred filter, `tag:xyz` search syntax.
- `deriveAutoTags` kept as empty hook for post-Task-7 LLM topic tags;
  research found all previous auto-tag chips redundant with row UI.
- Viewer window adds edit mode with debounced-save textarea; native
  title renamed to "Kon - Transcription Editor".
- Window minimums updated per GNOME HIG + WCAG reflow research:
  main 960x600, float 360x480, editor 560x520.
- Microphone picker filters raw ALSA strings (hw:, plughw:, front:,
  sysdefault:, null) and dedupes by CARD=X. New `description` field
  on DeviceInfo reads /proc/asound/cards so Blue Yeti shows as "Blue
  Microphones" instead of the short "Microphones" card name.
- GPU reporting fixed: get_runtime_capabilities now returns
  accelerators=[cpu,vulkan] and whisper.supports_gpu=true, matching
  the transcribe-rs whisper-vulkan feature linked unconditionally.
- ResizeHandles kept for macOS/Windows frameless: 12px edges, 20px
  corners via CSS vars, pointerdown + setPointerCapture, corners
  above edges in z-order, rendered as sibling (not child) of the
  animated layout root so `position: fixed` is viewport-relative.
- Dueling drag-region handlers removed — `data-tauri-drag-region` and
  manual `startDragging()` were stacked on the same elements; kept
  the manual handler which has the button/input early-return logic.

See HANDOVER.md for the full session log and deferred items.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/routes/+layout.svelte

@@ -6,10 +6,18 @@
   import TaskSidebar from "$lib/components/TaskSidebar.svelte";
   import Titlebar from "$lib/components/Titlebar.svelte";
   import ToastViewport from "$lib/components/ToastViewport.svelte";
+  import ResizeHandles from "$lib/components/ResizeHandles.svelte";
   import { hasTauriRuntime } from "$lib/utils/runtime.js";
-  import { loadOsInfo } from "$lib/utils/osInfo.js";
+  import { loadOsInfo, isLinux } from "$lib/utils/osInfo.js";
   import { page, settings, saveSettings } from "$lib/stores/page.svelte.js";
-  import { getPreferences, updatePreferences } from "$lib/stores/preferences.svelte.js";
+  import {
+    getPreferences,
+    updatePreferences,
+    applyExternalPreferences,
+    PREFERENCES_CHANGED_EVENT,
+  } from "$lib/stores/preferences.svelte.js";
+  import { getCurrentWindow } from "@tauri-apps/api/window";
+  import { listen } from "@tauri-apps/api/event";
   import { toasts } from "$lib/stores/toasts.svelte.js";
 
   import { page as sveltePage } from "$app/stores";
@@ -19,6 +27,12 @@
   const prefs = getPreferences();
   const tauriRuntimeAvailable = hasTauriRuntime();
 
+  // On Linux Kon uses native KWin/Mutter decorations (see
+  // src-tauri/tauri.linux.conf.json and windows.rs). Frameless custom
+  // chrome stays for macOS and Windows. Default to false so Linux users
+  // don't see a flash of custom titlebar before loadOsInfo resolves.
+  let useCustomChrome = $state(false);
+
 
   // Detect secondary windows (float, viewer) — they use +layout@.svelte
   // but as a fallback, hide chrome if the URL matches
@@ -158,6 +172,20 @@
     }
   }
 
+  // Cross-window preference sync: apply updates broadcast by any other
+  // window (float, viewer) while skipping our own echoes.
+  let unlistenPrefs = null;
+  async function setupPreferencesSync() {
+    if (!tauriRuntimeAvailable) return;
+    let ownLabel = null;
+    try { ownLabel = getCurrentWindow().label; } catch {}
+    unlistenPrefs = await listen(PREFERENCES_CHANGED_EVENT, (event) => {
+      const payload = event?.payload;
+      if (!payload || payload.source === ownLabel) return;
+      applyExternalPreferences(payload.prefs);
+    });
+  }
+
   // Capture global frontend errors and forward to the Rust error_log via
   // log_frontend_error. Best-effort: never let the error handler itself
   // throw, never crash the app over a logging failure.
@@ -198,12 +226,19 @@
     handleResize();
     window.addEventListener("resize", handleResize);
 
+    // Cross-window preference sync (no-op outside Tauri).
+    setupPreferencesSync();
+
     // Diagnostics: capture every uncaught frontend error to error_log.
     installGlobalErrorCapture();
 
     // OS detection: warm the cache so components can use modKeyLabel() /
-    // isMac() / isWayland() synchronously after first render.
-    loadOsInfo().catch(() => { /* fallback already populated */ });
+    // isMac() / isWayland() synchronously after first render. We also
+    // use the result to decide whether to render the custom Titlebar +
+    // ResizeHandles (non-Linux) or rely on native decorations (Linux).
+    loadOsInfo()
+      .then(() => { useCustomChrome = !isLinux(); })
+      .catch(() => { /* fallback already populated */ });
 
     if (!tauriRuntimeAvailable) {
       hotkeyBackend = "unavailable";
@@ -250,6 +285,9 @@
     if (unlistenEvdev) {
       unlistenEvdev();
     }
+    if (unlistenPrefs) {
+      unlistenPrefs();
+    }
   });
 </script>
 
@@ -261,7 +299,9 @@
   {@render children()}
 {:else}
   <div class="flex flex-col h-screen w-screen overflow-hidden grain">
-    <Titlebar />
+    {#if useCustomChrome}
+      <Titlebar />
+    {/if}
     <div class="flex flex-1 min-h-0 relative">
       {#if page.current !== "first-run"}
         <Sidebar />
@@ -282,3 +322,10 @@
      can call toasts.error(...), toasts.success(...) etc and have it render
      in the bottom-right of the viewport. (Day 3 of the upgrade plan) -->
 <ToastViewport />
+
+<!-- Invisible resize margins for frameless (macOS/Windows). On Linux we
+     use native decorations, so ResizeHandles would compete with the
+     compositor's own resize and is suppressed. -->
+{#if useCustomChrome}
+  <ResizeHandles />
+{/if}