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/lib/components/HotkeyRecorder.svelte

@@ -6,16 +6,17 @@
 
   const modifierKeys = new Set(["Control", "Shift", "Alt", "Meta"]);
 
-  function startRecording() {
-    recording = true;
-    captured = false;
-  }
-
   function handleKeyDown(e) {
+    // Capture-phase listener; guard still belts-and-braces.
     if (!recording) return;
     e.preventDefault();
     e.stopPropagation();
 
+    if (e.key === "Escape") {
+      recording = false;
+      return;
+    }
+
     // Wait for a non-modifier key
     if (modifierKeys.has(e.key)) return;
 
@@ -39,8 +40,21 @@
     setTimeout(() => { captured = false; }, 1500);
   }
 
-  function handleBlur() {
-    recording = false;
+  // Register the listener only while recording, at the capture phase so no
+  // descendant handler (or the parent layout's svelte:window keydown) can
+  // swallow the event first. Button-level onkeydown would require the
+  // button to hold keyboard focus after a click, which webkit2gtk on Linux
+  // does not guarantee.
+  $effect(() => {
+    if (!recording) return;
+    const handler = handleKeyDown;
+    document.addEventListener("keydown", handler, { capture: true });
+    return () => document.removeEventListener("keydown", handler, { capture: true });
+  });
+
+  function startRecording() {
+    recording = true;
+    captured = false;
   }
 
   let chips = $derived(settings.globalHotkey.split("+"));
@@ -55,8 +69,6 @@
         : 'bg-bg-input border-border hover:border-border'}
     border transition-all"
   onclick={startRecording}
-  onkeydown={handleKeyDown}
-  onblur={handleBlur}
   aria-label="Record hotkey"
 >
   {#if recording}