1.2.6: dedicated FontPicker component with in-line type previews

Replaces the bare <select> with a custom combobox that fits the
properties panel's visual language:

- Trigger looks like the other inputs (var(--bg)/var(--border)/
  var(--radius-sm)) and shows the selected font's name rendered in
  that font itself, with a rotating caret.
- Options live in a teleported popover anchored beneath the trigger.
  Each option renders its own label in its own typeface so the user
  sees what they're picking before applying it. Active row uses
  var(--accent-soft) to match the rest of the editor.
- Click-outside closes via window pointerdown; Escape closes and
  returns focus to the trigger.
- Storage shape simplified: textFontModel uses '' for system-sans
  instead of the literal 'system-sans' id, so the model field round-
  trips through JSON without a placeholder string ever leaking.

Updated PropertiesPanel test to walk the new picker (click trigger,
read options from .font-popover, click an option) instead of
dispatching a select 'change' event. Picker label text doubles as
the test selector — System Sans / Inter / Permanent Marker confirm
the option list is wired up.

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

src/version.ts

@@ -1,2 +1,2 @@
-export const APP_VERSION = '1.2.5'
+export const APP_VERSION = '1.2.6'
 export const APP_NAME = 'RUWIO'