feat: named server sets — save/apply the Active/Disabled split (#52)

Sets live in the config under _bccServerSets (bcc-owned, ignored by
Claude, travels with the file). Apply enables exactly the set's members
and parks the rest; vanished members are reported, not fatal. GUI row:
set combo + Apply + Save set… + delete.

Closes #52

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bcc.py

@@ -38,6 +38,7 @@ from PySide6.QtWidgets import (
     QGridLayout,
     QHBoxLayout,
     QHeaderView,
+    QInputDialog,
     QLabel,
     QLineEdit,
     QListWidget,
@@ -1692,6 +1693,30 @@ class MainWindow(QMainWindow):
         self.search_box.textChanged.connect(self._on_search_changed)
         v.addWidget(self.search_box)
 
+        # Named server sets (issue #52): apply a saved Active/Disabled split
+        # in one click. Sets live in the config file under _bccServerSets.
+        sets_row = QHBoxLayout()
+        sets_lbl = QLabel("Set")
+        sets_lbl.setObjectName("muted")
+        sets_row.addWidget(sets_lbl)
+        self.sets_combo = QComboBox()
+        self.sets_combo.setMinimumWidth(120)
+        sets_row.addWidget(self.sets_combo, 1)
+        self.apply_set_btn = QPushButton("Apply")
+        self.apply_set_btn.setToolTip("Enable exactly this set's servers; disable the rest")
+        self.apply_set_btn.clicked.connect(self._apply_selected_set)
+        sets_row.addWidget(self.apply_set_btn)
+        self.save_set_btn = QPushButton("Save set…")
+        self.save_set_btn.setToolTip("Save the current Active/Disabled split as a named set")
+        self.save_set_btn.clicked.connect(self._save_set)
+        sets_row.addWidget(self.save_set_btn)
+        self.del_set_btn = QPushButton("−")
+        self.del_set_btn.setToolTip("Delete the selected set")
+        self.del_set_btn.setMaximumWidth(32)
+        self.del_set_btn.clicked.connect(self._delete_set)
+        sets_row.addWidget(self.del_set_btn)
+        v.addLayout(sets_row)
+
         # Active and Disabled sections live in a vertical splitter so the user
         # can drag the divider instead of being stuck with a fixed-height
         # disabled list.
@@ -1892,6 +1917,7 @@ class MainWindow(QMainWindow):
         self._undo_stack.clear()
         self.undo_btn.setEnabled(False)
         self._health.clear()  # health results are per-profile; a fresh load invalidates them
+        self._refresh_sets_combo()  # sets are per-config; repopulate from the loaded file
         self._refresh_tables(select_index=0 if self.servers else -1)
         self._update_status(saved=False)
         if repaired:
@@ -1991,6 +2017,73 @@ class MainWindow(QMainWindow):
         cur = self._current_index()
         self._refresh_tables(select_index=cur if cur >= 0 else None)
 
+    # --- named server sets (issue #52) ------------------------------------ #
+    def _refresh_sets_combo(self, select: str | None = None):
+        sets = core.list_server_sets(self.full_config)
+        self.sets_combo.blockSignals(True)
+        self.sets_combo.clear()
+        for name in sorted(sets):
+            self.sets_combo.addItem(name)
+        if select is not None:
+            idx = self.sets_combo.findText(select)
+            if idx >= 0:
+                self.sets_combo.setCurrentIndex(idx)
+        self.sets_combo.blockSignals(False)
+        has_sets = bool(sets)
+        self.apply_set_btn.setEnabled(has_sets)
+        self.del_set_btn.setEnabled(has_sets)
+
+    def _apply_selected_set(self):
+        name = self.sets_combo.currentText()
+        sets = core.list_server_sets(self.full_config)
+        if name not in sets:
+            return
+        self._push_undo()
+        missing = core.apply_server_set(self.servers, sets[name])
+        self._refresh_tables(select_index=self._current_index() if self.servers else None)
+        self._mark_dirty()
+        on = sum(1 for s in self.servers if s.enabled)
+        msg = f"Applied set “{name}”  ·  {on} enabled. Review and Save."
+        if missing:
+            msg += f"  ⚠ no longer in this config: {', '.join(missing)}"
+        self.status.setText(msg)
+
+    def _save_set(self):
+        name, ok = QInputDialog.getText(
+            self,
+            "Save server set",
+            "Set name (saves which servers are currently Active):",
+            text=self.sets_combo.currentText(),
+        )
+        name = name.strip()
+        if not ok or not name:
+            return
+        if name in core.list_server_sets(self.full_config) and (
+            QMessageBox.question(self, "Set exists", f"Replace set “{name}”?")
+            != QMessageBox.StandardButton.Yes
+        ):
+            return
+        members = core.save_server_set(self.full_config, name, self.servers)
+        self._refresh_sets_combo(select=name)
+        self._mark_dirty()  # the set is written on the next Save
+        self.status.setText(
+            f"Set “{name}” saved ({len(members)} server(s)). Press Save to write it."
+        )
+
+    def _delete_set(self):
+        name = self.sets_combo.currentText()
+        if not name:
+            return
+        if (
+            QMessageBox.question(self, "Delete set", f"Delete set “{name}”?")
+            != QMessageBox.StandardButton.Yes
+        ):
+            return
+        if core.delete_server_set(self.full_config, name):
+            self._refresh_sets_combo()
+            self._mark_dirty()
+            self.status.setText(f"Set “{name}” deleted. Press Save to write the change.")
+
     # --- test all (spawn-test every enabled local server) ---------------- #
     def _test_all_servers(self):
         targets = [s for s in self.servers if s.enabled and s.kind == "stdio"]