feat: manage canvases with custom name and icon

Make designs (canvases) fully user-manageable: create with a chosen name
and icon, rename, change icon, and delete. Replaces the hardcoded
"New Electrical Design" button with a generic "New Canvas" flow.

- Add Design.icon column + migration that backfills legacy rows
  (electrical -> zap, others -> dashboard)
- DesignModal: name input + curated lucide icon picker (create + edit)
- Sidebar switcher gains per-canvas edit/delete; delete guards the last
  canvas and confirms
- designStore: addDesign/updateDesign/removeDesign with active reassignment
- Fix data loss on design switch: abort load when the save fails and keep
  unsaved edits; skip the save-old step when the previous canvas was deleted
- designsApi create/update carry icon; design_type kept for back-compat

Tests: backend design CRUD (icon + cascade + last-canvas guard), designStore
actions, designIcons resolver, DesignModal create/edit/validation.

ha-relevant: yes

backend/app/api/routes/designs.py

@@ -25,7 +25,7 @@ async def create_design(
     db: AsyncSession = Depends(get_db),
     _: str = Depends(get_current_user),
 ) -> DesignResponse:
-    design = Design(name=body.name, design_type=body.design_type)
+    design = Design(name=body.name, design_type=body.design_type, icon=body.icon)
     db.add(design)
     await db.flush()
     # Create empty canvas state for the new design
@@ -47,6 +47,8 @@ async def update_design(
         raise HTTPException(404, "Design not found")
     if body.name is not None:
         design.name = body.name
+    if body.icon is not None:
+        design.icon = body.icon
     await db.commit()
     await db.refresh(design)
     return DesignResponse.model_validate(design)

backend/app/db/database.py

@@ -183,6 +183,19 @@ async def init_db() -> None:
             ")",
             label="designs.table",
         )
+        # Add user-chosen icon to designs (idempotent), then backfill existing rows
+        # so legacy designs keep a sensible icon based on their original type.
+        await _try_migrate(
+            conn, "ALTER TABLE designs ADD COLUMN icon VARCHAR", label="designs.icon",
+        )
+        with suppress(OperationalError):
+            await conn.exec_driver_sql(
+                "UPDATE designs SET icon = 'zap' WHERE icon IS NULL AND design_type = 'electrical'"
+            )
+        with suppress(OperationalError):
+            await conn.exec_driver_sql(
+                "UPDATE designs SET icon = 'dashboard' WHERE icon IS NULL"
+            )
         # Seed default Network Topology design if designs table is empty
         _default_design_id = str(_uuid_mod.uuid4())
         row = await conn.exec_driver_sql("SELECT COUNT(*) FROM designs")
@@ -190,8 +203,8 @@ async def init_db() -> None:
         count = count_row[0] if count_row else 0
         if count == 0:
             await conn.exec_driver_sql(
-                "INSERT INTO designs (id, name, design_type, created_at, updated_at) "
-                "VALUES (?, 'Network Topology', 'network', datetime('now'), datetime('now'))",
+                "INSERT INTO designs (id, name, design_type, icon, created_at, updated_at) "
+                "VALUES (?, 'Network Topology', 'network', 'dashboard', datetime('now'), datetime('now'))",
                 (_default_design_id,),
             )
         else:

backend/app/db/models.py

@@ -22,6 +22,7 @@ class Design(Base):
     id: Mapped[str] = mapped_column(String, primary_key=True, default=_uuid)
     name: Mapped[str] = mapped_column(String, nullable=False)
     design_type: Mapped[str] = mapped_column(String, nullable=False, default="network")
+    icon: Mapped[str | None] = mapped_column(String, nullable=True, default="dashboard")
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
     updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now, onupdate=_now)
 

backend/app/schemas/designs.py

@@ -5,17 +5,22 @@ from pydantic import BaseModel
 
 class DesignCreate(BaseModel):
     name: str
-    design_type: str = "electrical"
+    icon: str = "dashboard"
+    # Vestigial: kept for backward compatibility. The UI no longer branches on it;
+    # the chosen icon now drives presentation. Defaults to a generic canvas.
+    design_type: str = "network"
 
 
 class DesignUpdate(BaseModel):
     name: str | None = None
+    icon: str | None = None
 
 
 class DesignResponse(BaseModel):
     id: str
     name: str
     design_type: str
+    icon: str | None = None
     created_at: datetime
     updated_at: datetime