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/float/+layout@.svelte

@@ -4,12 +4,20 @@
   import { listen } from "@tauri-apps/api/event";
   import { getCurrentWindow } from "@tauri-apps/api/window";
   import { settings } from "$lib/stores/page.svelte.js";
-  import { getPreferences, updatePreferences } from "$lib/stores/preferences.svelte.js";
+  import {
+    getPreferences,
+    updatePreferences,
+    applyExternalPreferences,
+    PREFERENCES_CHANGED_EVENT,
+  } from "$lib/stores/preferences.svelte.js";
   import Titlebar from "$lib/components/Titlebar.svelte";
+  import { loadOsInfo, isLinux } from "$lib/utils/osInfo.js";
 
   let { children } = $props();
   let glowing = $state(false);
   let unlistenFocus = null;
+  let unlistenPrefs = null;
+  let useCustomChrome = $state(false);
 
   const prefs = getPreferences();
 
@@ -34,6 +42,9 @@
   }
 
   onMount(async () => {
+    loadOsInfo()
+      .then(() => { useCustomChrome = !isLinux(); })
+      .catch(() => {});
     try {
       unlistenFocus = await listen("task-window-focus", () => {
         glowing = true;
@@ -43,10 +54,21 @@
         if (input) input.focus();
       });
     } catch {}
+
+    try {
+      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);
+      });
+    } catch {}
   });
 
   onDestroy(() => {
     if (unlistenFocus) unlistenFocus();
+    if (unlistenPrefs) unlistenPrefs();
   });
 
   // Escape to close
@@ -59,7 +81,11 @@
 
 <svelte:window onkeydown={handleKeydown} />
 
-<div class="h-screen w-screen overflow-hidden grain rounded-lg border border-border shadow-xl animate-float-enter {glowing ? 'animate-glow-pulse' : ''}">
-  <Titlebar compact />
-  {@render children()}
+<div class="h-screen w-screen overflow-hidden grain border border-border shadow-xl animate-float-enter flex flex-col {glowing ? 'animate-glow-pulse' : ''}">
+  {#if useCustomChrome}
+    <Titlebar compact />
+  {/if}
+  <div class="flex-1 min-h-0 overflow-hidden">
+    {@render children()}
+  </div>
 </div>