feat: add winking expression (v0.1.1)

Buddy now has a fourth mood tone — wink — with one eye closed, an
asymmetric smirk, and rosier cheeks. Renders as a small variant
inside the existing inline-SVG sprite (still zero image files, no
new assets). When overall mood is >= 75, there's a 30% chance on
each page render that the wink replaces the standard happy face —
gives the pet a touch of unpredictable personality.

Why this commit exists: v0.1.0 had three tones (happy / neutral /
sad). Adding wink is the smallest possible demo that the SVG
expression engine is properly extensible — every future mood,
state, accessory or species can land via the same pattern. ~20
lines of PHP, ~2 lines of CSS, no bundle weight, no dependencies.

CHANGES
- inc/sprite.php: wink added to allowed-tones list. Left eye
  renders as a closed-eye arc instead of the open circle. Mouth
  shifts to an asymmetric smirk. Cheek opacity 0.55 → 0.75 for
  extra cheekiness.
- inc/state.php: buddy_mood_label() returns wink ~30% of the time
  when mood >= 75.
- assets/css/buddy.css: new .buddy-widget__mood--wink and
  .buddy-main__mood--wink rules — warm amber pill.
- About-page version-history leads with v0.1.1; v0.1.0 demoted.

VERSION
- buddy.php header 0.1.0 → 0.1.1
- BUDDY_VERSION constant 0.1.0 → 0.1.1

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/css/buddy.css

@@ -57,6 +57,7 @@
     vertical-align: middle;
 }
 .buddy-widget__mood--happy   { background:#e8f5ea; color:#1b6f2d; }
+.buddy-widget__mood--wink    { background:#fef3c7; color:#92400e; }
 .buddy-widget__mood--neutral { background:#f0f0f1; color:#3c434a; }
 .buddy-widget__mood--sad     { background:#fcf0f1; color:#8a2424; }
 
@@ -138,6 +139,7 @@
     vertical-align: middle;
 }
 .buddy-main__mood--happy   { background:#e8f5ea; color:#1b6f2d; }
+.buddy-main__mood--wink    { background:#fef3c7; color:#92400e; }
 .buddy-main__mood--neutral { background:#f0f0f1; color:#3c434a; }
 .buddy-main__mood--sad     { background:#fcf0f1; color:#8a2424; }