GUI: assembly subtree + connection right-click menu

Parts tab is now a QTreeWidget: connected boards group under an "⛓ Assembly"
node (expandable) showing their members; standalone boards stay top-level. A
board with features is flagged ⊕. Multi-select still drives controller.selected
(selecting an assembly node selects its members).

Right-click menu: Back off connections (explode), Re-fit connections (assemble),
Break this board's connections / Break all. Controller wrappers: explode/
assemble/break_connections/groups.

83 tests pass; GUI imports clean (live tree behavior needs a display to verify).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -119,8 +119,17 @@ pytest                            # 25 tests
    the board's yaw/tilt/roll via `matrix_to_ypr` (inverse of `Part.local_frame`'s
    Rz·Ry(-tilt)·Rx(roll)); `Part.feature_world_frame` gives each feature's world
    point/normal/u/v. Features also have `rotation_deg` (spin about the face
-   normal) to line up cross-sections. CLI `connect`; voice `wood-connect`. Not
+   normal) to line up cross-sections. CLI `connect`; voice `wood-connect`.
-   yet: countersinks, click-a-face-to-place.
+3. **Connections / assemblies**: `connect` RECORDS a `Connection`; connected
+   boards form an assembly (`scene.groups()`, connection-graph union-find). They
+   stay separate boards (not fused — cut list & disassembly keep working). Ops:
+   `scene.explode(d)` backs each moving board off along its joint axis,
+   `assemble()` re-seats (reverse), `disconnect(cid/part)` breaks (pieces stay
+   put). `_seat()` is the shared mate math. CLI `connections/disconnect/explode/
+   assemble`; voice `wood-explode/assemble/disconnect`. The GUI Parts tab is a
+   QTreeWidget grouping connected boards under an assembly node, with a
+   right-click menu (back off / re-fit / break). Not yet: countersinks,
+   click-a-face-to-place, per-assembly naming/rename.
 2. **Latency** ~7–13s per utterance (one `claude -p` call).
 3. Voice path (`--voice`) reuses `dictate`; the driver loop is hardened against
    failures but the mic path isn't exercised in the unit tests.

src/woodshop/gui/controller.py

@@ -290,6 +290,19 @@ class Controller(QObject):
         self.scene.edit_feature(feat.id, **dims)
         self._commit(f"Fitted {feat.id} to {target_fid}.")
 
+    def explode(self, distance: float = 3.0) -> None:
+        self._do(lambda: self.scene.explode(distance))
+
+    def assemble(self) -> None:
+        self._do(self.scene.assemble)
+
+    def break_connections(self, part_id: str | None = None) -> None:
+        self._do(lambda: self.scene.disconnect(part=part_id) if part_id
+                 else self.scene.disconnect())
+
+    def groups(self) -> list[list[str]]:
+        return self.scene.groups()
+
     def make_connection(self, target_fid: str) -> None:
         """Move/orient the target's board so its feature seats into the active one."""
         feat = self.active_feature_obj()

src/woodshop/gui/panels.py

@@ -6,7 +6,7 @@ from __future__ import annotations
 from PySide6.QtCore import Qt
 from PySide6.QtWidgets import (QAbstractItemView, QDoubleSpinBox, QFormLayout,
                                QGridLayout, QGroupBox, QInputDialog, QLabel,
-                               QListWidget, QListWidgetItem, QPushButton,
+                               QMenu, QPushButton, QTreeWidget, QTreeWidgetItem,
                                QVBoxLayout, QWidget)
 
 from .controller import Controller
@@ -19,12 +19,15 @@ class PartsPanel(QWidget):
         self._loading = False
 
         root = QVBoxLayout(self)
-        root.addWidget(QLabel("<b>Parts</b>"))
+        root.addWidget(QLabel("<b>Parts</b>  <span style='color:#888'>(connected boards group into assemblies)</span>"))
 
-        self.list = QListWidget()
+        self.tree = QTreeWidget()
-        self.list.setSelectionMode(QAbstractItemView.ExtendedSelection)  # Ctrl/Shift multi-select
+        self.tree.setHeaderHidden(True)
-        self.list.itemSelectionChanged.connect(self._on_row_selected)
+        self.tree.setSelectionMode(QAbstractItemView.ExtendedSelection)  # Ctrl/Shift multi-select
-        root.addWidget(self.list, 1)
+        self.tree.itemSelectionChanged.connect(self._on_row_selected)
+        self.tree.setContextMenuPolicy(Qt.CustomContextMenu)
+        self.tree.customContextMenuRequested.connect(self._context_menu)
+        root.addWidget(self.tree, 1)
 
         box = QGroupBox("Selected")
         bl = QVBoxLayout(box)
@@ -63,18 +66,36 @@ class PartsPanel(QWidget):
         self.c.changed.connect(self.refresh)
         self.refresh()
 
+    def _part_label(self, p) -> str:
+        name = f" · {p.name}" if p.name else ""
+        extra = " ⊕" if p.features else ""
+        return f"{p.id}  {p.stock} {p.length_in:g}\"{name}{extra}"
+
+    def _add_leaf(self, parent, pid, selected):
+        p = next((q for q in self.c.scene.parts if q.id == pid), None)
+        if not p:
+            return
+        item = QTreeWidgetItem(parent, [self._part_label(p)])
+        item.setData(0, Qt.UserRole, pid)
+        if pid in selected:
+            item.setSelected(True)
+
     # ----- refresh from scene ------------------------------------------
     def refresh(self) -> None:
         self._loading = True
-        self.list.clear()
+        self.tree.clear()
         selected = set(self.c.selected)
-        for p in self.c.scene.parts:
+        by_id = {p.id: p for p in self.c.scene.parts}
-            name = f" · {p.name}" if p.name else ""
+        for group in self.c.groups():
-            item = QListWidgetItem(f"{p.id}  {p.stock} {p.length_in:g}\"{name}")
+            if len(group) > 1:                       # an assembly -> parent node
-            item.setData(Qt.UserRole, p.id)
+                names = [by_id[i].name or i for i in group if i in by_id]
-            self.list.addItem(item)
+                node = QTreeWidgetItem(self.tree, [f"⛓ Assembly: {' + '.join(names)}"])
-            if p.id in selected:
+                node.setData(0, Qt.UserRole, None)
-                item.setSelected(True)
+                node.setExpanded(True)
+                for pid in group:
+                    self._add_leaf(node, pid, selected)
+            elif group:
+                self._add_leaf(self.tree, group[0], selected)
 
         part = self._selected_part()
         if part:
@@ -96,11 +117,36 @@ class PartsPanel(QWidget):
         return next((p for p in self.c.scene.parts if p.id == pid), None)
 
     # ----- handlers ----------------------------------------------------
+    def _selected_ids(self) -> list[str]:
+        ids = []
+        for it in self.tree.selectedItems():
+            pid = it.data(0, Qt.UserRole)
+            if pid:                                  # a part leaf
+                ids.append(pid)
+            else:                                    # an assembly node -> its members
+                ids += [it.child(i).data(0, Qt.UserRole) for i in range(it.childCount())]
+        return list(dict.fromkeys(ids))
+
     def _on_row_selected(self) -> None:
         if self._loading:
             return
-        ids = [it.data(Qt.UserRole) for it in self.list.selectedItems()]
+        self.c.set_selected(self._selected_ids())
-        self.c.set_selected(ids)
+
+    def _context_menu(self, pos) -> None:
+        item = self.tree.itemAt(pos)
+        menu = QMenu(self)
+        if self.c.scene.connections:
+            menu.addAction("Back off connections", lambda: self.c.explode(3.0))
+            menu.addAction("Re-fit connections", self.c.assemble)
+            if item:
+                pid = item.data(0, Qt.UserRole)
+                if pid:
+                    menu.addAction("Break this board's connections",
+                                   lambda: self.c.break_connections(pid))
+            menu.addAction("Break all connections", lambda: self.c.break_connections())
+        if menu.isEmpty():
+            menu.addAction("No connections yet").setEnabled(False)
+        menu.exec(self.tree.viewport().mapToGlobal(pos))
 
     def _rename(self) -> None:
         part = self._selected_part()