feat(ui): Steam-style conflict dialog

Replaces the radio+continue layout with a Steam Cloud Conflict
lookalike: uppercase title with circled-! glyph, three-line body
copy, two large card-buttons (Cloud Save / Local Save) each showing
icon + label + 'Modified <date>', Cancel bottom-right. Card click
commits the choice and dismisses — no separate Continue button.

Background switched to Steam-blue (#1b2838) instead of Prism dark
so the dialog reads as a 'pay attention' moment rather than another
status pane.

Card glyphs are unicode placeholders (☁ / ▢) — easy SVG swap later
if we want crisp HDD/cloud icons.

API change:
  prompt_conflict_qt(local_summary, remote_summary)
    → prompt_conflict_qt(local_modified, remote_modified, save_label)
  Caller now passes pre-formatted timestamp strings + an optional
  noun phrase ('Minecraft save').

cloud_sync/ui_qt.py

@@ -278,77 +278,194 @@ def prompt_login_qt() -> str | None:
 # ---------------------------------------------------------------------------
 
 
+_CONFLICT_QSS = """
+QDialog { background: #1b2838; }
+QLabel#title {
+    color: white;
+    font-size: 20pt;
+    font-weight: bold;
+    letter-spacing: 2px;
+}
+QLabel#warning {
+    color: #1b2838;
+    background: #d6dde6;
+    border-radius: 16px;
+    font-size: 18pt;
+    font-weight: bold;
+    qproperty-alignment: AlignCenter;
+    min-width: 32px;
+    max-width: 32px;
+    min-height: 32px;
+    max-height: 32px;
+}
+QLabel#body {
+    color: #a9b3bf;
+    font-size: 10pt;
+}
+QLabel#note {
+    color: #7d8a99;
+    font-size: 9pt;
+}
+QFrame#card {
+    background: #2a3f5a;
+    border: 1px solid transparent;
+    border-radius: 4px;
+}
+QFrame#card:hover {
+    background: #34507a;
+    border: 1px solid #5b8fc7;
+}
+QLabel#cardTitle {
+    color: white;
+    font-size: 13pt;
+    font-weight: bold;
+    background: transparent;
+}
+QLabel#cardSubtitle {
+    color: #a9b3bf;
+    font-size: 9pt;
+    background: transparent;
+}
+QLabel#cardIcon {
+    color: white;
+    font-size: 24pt;
+    background: transparent;
+}
+QPushButton#cancel {
+    background: #2a475e;
+    color: white;
+    border: 1px solid #4a6580;
+    border-radius: 2px;
+    padding: 8px 24px;
+    font-size: 10pt;
+}
+QPushButton#cancel:hover { background: #355d7d; }
+QPushButton#cancel:pressed { background: #1f3548; }
+"""
+
+
 def prompt_conflict_qt(
-    local_summary: str,
+    local_modified: str,
-    remote_summary: str,
+    remote_modified: str,
+    save_label: str = "Minecraft save",
 ) -> str:
-    """Ask how to resolve a divergence.
+    """Steam-Cloud-Conflict-styled dialog.
+
+    Args:
+        local_modified: human-readable "Saturday, February 12 at 12:28 AM"
+        remote_modified: same, but for the cloud snapshot
+        save_label: noun phrase for body copy (e.g. "Minecraft save").
 
     Returns one of: ``"keep_local"``, ``"use_remote"``, ``"cancel"``.
+    Visually mirrors Steam's Cloud Conflict modal: header with warning
+    glyph + uppercase title, two large card buttons (cloud / local),
+    Cancel bottom-right. Card click commits and dismisses.
     """
-    QtWidgets, QtCore, _ = import_qt()
+    QtWidgets, QtCore, Signal = import_qt()
     app_existed = QtWidgets.QApplication.instance() is not None
     app = QtWidgets.QApplication.instance() or QtWidgets.QApplication(sys.argv)
     if not app_existed:
         _apply_prism_dark(app)
 
+    class _Card(QtWidgets.QFrame):
+        clicked = Signal()
+
+        def __init__(self, glyph: str, title: str, subtitle: str) -> None:
+            super().__init__()
+            self.setObjectName("card")
+            self.setCursor(QtCore.Qt.CursorShape.PointingHandCursor)
+            self.setSizePolicy(
+                QtWidgets.QSizePolicy.Policy.Expanding,
+                QtWidgets.QSizePolicy.Policy.Fixed,
+            )
+            row = QtWidgets.QHBoxLayout(self)
+            row.setContentsMargins(18, 14, 18, 14)
+            row.setSpacing(16)
+            icon = QtWidgets.QLabel(glyph)
+            icon.setObjectName("cardIcon")
+            icon.setFixedWidth(40)
+            icon.setAlignment(QtCore.Qt.AlignmentFlag.AlignCenter)
+            row.addWidget(icon)
+            text_col = QtWidgets.QVBoxLayout()
+            text_col.setSpacing(2)
+            t = QtWidgets.QLabel(title)
+            t.setObjectName("cardTitle")
+            s = QtWidgets.QLabel(subtitle)
+            s.setObjectName("cardSubtitle")
+            text_col.addWidget(t)
+            text_col.addWidget(s)
+            row.addLayout(text_col, 1)
+
+        def mousePressEvent(self, _event: Any) -> None:  # noqa: N802
+            self.clicked.emit()
+
     dialog = QtWidgets.QDialog()
     dialog.setWindowTitle("Cloud sync — conflict")
-    dialog.setFixedSize(520, 320)
+    dialog.setFixedSize(640, 460)
+    dialog.setStyleSheet(_CONFLICT_QSS)
 
-    layout = QtWidgets.QVBoxLayout(dialog)
+    outer = QtWidgets.QVBoxLayout(dialog)
-    layout.setContentsMargins(20, 20, 20, 20)
+    outer.setContentsMargins(28, 24, 28, 20)
-    layout.setSpacing(10)
+    outer.setSpacing(14)
 
-    title = QtWidgets.QLabel("Local and cloud diverged")
+    header = QtWidgets.QHBoxLayout()
-    font = title.font()
+    header.setSpacing(12)
-    font.setBold(True)
+    warning = QtWidgets.QLabel("!")
-    font.setPointSize(font.pointSize() + 2)
+    warning.setObjectName("warning")
-    title.setFont(font)
+    header.addWidget(warning)
-    layout.addWidget(title)
+    title = QtWidgets.QLabel("CLOUD CONFLICT")
+    title.setObjectName("title")
+    header.addWidget(title)
+    header.addStretch(1)
+    outer.addLayout(header)
 
-    summary = QtWidgets.QLabel(
+    body = QtWidgets.QLabel(
-        f"Local changes since last sync:\n  {local_summary}\n\n"
+        f"Your local {save_label} conflicts with what is stored in the cloud. "
-        f"Cloud has newer changes from another machine:\n  {remote_summary}\n\n"
+        f"Whichever save data you choose to keep will be synced to this device "
-        f"What should we do?"
+        f"and the cloud. The option you choose not to keep will be overwritten."
     )
-    summary.setWordWrap(True)
+    body.setObjectName("body")
-    layout.addWidget(summary)
+    body.setWordWrap(True)
+    outer.addWidget(body)
 
-    keep_local = QtWidgets.QRadioButton(
+    outer.addSpacing(6)
-        "Keep local — skip pull. Next exit will overwrite cloud."
-    )
-    use_remote = QtWidgets.QRadioButton(
-        "Use cloud — overwrite local files with the cloud version."
-    )
-    cancel_launch = QtWidgets.QRadioButton(
-        "Cancel launch — don't start Minecraft until I resolve manually."
-    )
-    keep_local.setChecked(True)
-    layout.addWidget(keep_local)
-    layout.addWidget(use_remote)
-    layout.addWidget(cancel_launch)
 
-    layout.addStretch(1)
+    cloud_card = _Card("☁", "Cloud Save", f"Modified {remote_modified}")
+    local_card = _Card("▢", "Local Save", f"Modified {local_modified}")
+    outer.addWidget(cloud_card)
+    outer.addWidget(local_card)
 
-    button_row = QtWidgets.QHBoxLayout()
+    outer.addStretch(1)
-    button_row.addStretch(1)
+
-    confirm = QtWidgets.QPushButton("Continue")
+    foot = QtWidgets.QHBoxLayout()
-    confirm.setDefault(True)
+    note = QtWidgets.QLabel(
-    button_row.addWidget(confirm)
+        "Note: You will need to choose a version to keep before launching the game."
-    layout.addLayout(button_row)
+    )
+    note.setObjectName("note")
+    note.setWordWrap(True)
+    foot.addWidget(note, 1)
+    cancel = QtWidgets.QPushButton("Cancel")
+    cancel.setObjectName("cancel")
+    foot.addWidget(cancel)
+    outer.addLayout(foot)
 
     chosen: dict[str, str] = {"value": "cancel"}
 
-    def on_confirm() -> None:
+    def pick_remote() -> None:
-        if keep_local.isChecked():
+        chosen["value"] = "use_remote"
-            chosen["value"] = "keep_local"
-        elif use_remote.isChecked():
-            chosen["value"] = "use_remote"
-        else:
-            chosen["value"] = "cancel"
         dialog.accept()
 
-    confirm.clicked.connect(on_confirm)
+    def pick_local() -> None:
+        chosen["value"] = "keep_local"
+        dialog.accept()
+
+    def pick_cancel() -> None:
+        chosen["value"] = "cancel"
+        dialog.reject()
+
+    cloud_card.clicked.connect(pick_remote)
+    local_card.clicked.connect(pick_local)
+    cancel.clicked.connect(pick_cancel)
+
     dialog.exec()
     return chosen["value"]