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-tauri/src/commands/models.rs

@@ -243,9 +243,12 @@ pub fn get_runtime_capabilities(
         .map(|entry| model_capability(entry, &parakeet))
         .collect();
 
+    // Kon's desktop build links transcribe-rs with the `whisper-vulkan`
+    // feature unconditionally (see crates/transcription/Cargo.toml), so
+    // whisper.cpp boots with Vulkan backend on any machine with a Vulkan
+    // loader + ICD. Parakeet (ONNX) still runs on CPU. Reflect both.
     Ok(RuntimeCapabilities {
-        // Current desktop build ships CPU-only inference backends.
-        accelerators: vec!["cpu".into()],
+        accelerators: vec!["cpu".into(), "vulkan".into()],
         engines: vec![
             EngineRuntimeCapabilities {
                 id: "whisper".into(),
@@ -254,7 +257,7 @@ pub fn get_runtime_capabilities(
                 loaded_model_id: whisper
                     .loaded_model_id()
                     .map(|model_id| model_id.to_string()),
-                supports_gpu: false,
+                supports_gpu: true,
                 models: whisper_models,
             },
             EngineRuntimeCapabilities {