Match history and win rate

Every finished match goes into a small sqlite database: mode, deck, both
classes, result, turn count and who started. The result tag arrives in the
last turn of the match, so the record is written then, not when the game
object is closed (that only happens once the next match starts). The unique
key is the session directory plus the match start time, so importing old
session logs into the same database can be repeated without duplicates.

The new window (from the menu) shows the totals, the win rate by deck and by
opponent class, and the recent matches. Classes are drawn as hero portraits
cut from the card render, with the class colour as a placeholder until the
image is downloaded. Every table sorts by any column: the sort key is hidden
data, not the visible text, so dates, turn counts and results sort correctly,
and numeric columns start descending.

tools/import_history.py backfills the database from the session logs already
on disk, tests/test_history.py covers the date handling, the idempotency and
the win rate maths.

ui/widgets.py

@@ -8,7 +8,7 @@ görselle birlikte satır tanınabilir oluyor.
 
 from __future__ import annotations
 
-from PyQt6.QtCore import QPoint, QRect, QSize, Qt, QTimer
+from PyQt6.QtCore import QPoint, QRect, QRectF, QSize, Qt, QTimer
 from PyQt6.QtGui import (
     QColor,
     QFont,
@@ -31,6 +31,57 @@ PREVIEW_DELAY_MS = 200
 HIDE_DELAY_MS = 140
 PREVIEW_GAP = 8
 
+# Kahraman kartının render'ında yüzün bulunduğu kare: sol kenar, üst kenar ve
+# kenar uzunluğu, kart genişliğinin oranı olarak. Altın çerçeve dışarıda kalsın
+# diye deneyerek bulundu.
+PORTRAIT_CROP = (0.33, 0.18, 0.34)
+
+
+def _circle(size: int) -> QPainterPath:
+    path = QPainterPath()
+    path.addEllipse(QRectF(0.0, 0.0, float(size), float(size)))
+    return path
+
+
+def color_dot(color: str, size: int) -> QPixmap:
+    """Sınıf rengiyle dolu daire. Portre inene kadarki yer tutucu."""
+    pixmap = QPixmap(size, size)
+    pixmap.fill(QColor(0, 0, 0, 0))
+    painter = QPainter(pixmap)
+    painter.setRenderHint(QPainter.RenderHint.Antialiasing)
+    painter.fillPath(_circle(size), QColor(color))
+    painter.end()
+    return pixmap
+
+
+def hero_portrait(path, size: int) -> QPixmap | None:
+    """Kahraman kartının render'ından daire portre keser."""
+    source = QPixmap(str(path))
+    if source.isNull():
+        return None
+    left, top, side = PORTRAIT_CROP
+    crop = source.copy(
+        QRect(
+            int(source.width() * left),
+            int(source.height() * top),
+            int(source.width() * side),
+            int(source.width() * side),
+        )
+    ).scaled(
+        size,
+        size,
+        Qt.AspectRatioMode.KeepAspectRatioByExpanding,
+        Qt.TransformationMode.SmoothTransformation,
+    )
+    pixmap = QPixmap(size, size)
+    pixmap.fill(QColor(0, 0, 0, 0))
+    painter = QPainter(pixmap)
+    painter.setRenderHint(QPainter.RenderHint.Antialiasing)
+    painter.setClipPath(_circle(size))
+    painter.drawPixmap(0, 0, crop)
+    painter.end()
+    return pixmap
+
 
 class ElidedLabel(QLabel):
     """Metni kısaltarak gösteren, genişliği pencereye dayatmayan etiket.