feat: resizable nodes with width/height persistence

Add NodeResizer to BaseNode so users can drag corners to resize any node.
Persist width/height through the full stack: DB model, schemas, canvas
save/load route, and migration for existing databases.

Add tests covering save, update, clear, and load of node dimensions.

backend/app/db/database.py

@@ -52,6 +52,10 @@ async def init_db() -> None:
             await conn.exec_driver_sql("ALTER TABLE nodes ADD COLUMN disk_gb REAL")
         with suppress(Exception):
             await conn.exec_driver_sql("ALTER TABLE nodes ADD COLUMN show_hardware BOOLEAN NOT NULL DEFAULT 0")
+        with suppress(Exception):
+            await conn.exec_driver_sql("ALTER TABLE nodes ADD COLUMN width REAL")
+        with suppress(Exception):
+            await conn.exec_driver_sql("ALTER TABLE nodes ADD COLUMN height REAL")
 
 
 async def get_db() -> AsyncGenerator[AsyncSession, None]:

backend/app/db/models.py

@@ -42,6 +42,8 @@ class Node(Base):
     ram_gb: Mapped[float | None] = mapped_column(Float, nullable=True)
     disk_gb: Mapped[float | None] = mapped_column(Float, nullable=True)
     show_hardware: Mapped[bool] = mapped_column(Boolean, default=False)
+    width: Mapped[float | None] = mapped_column(Float, nullable=True)
+    height: Mapped[float | None] = mapped_column(Float, nullable=True)
     last_seen: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     response_time_ms: Mapped[int | None] = mapped_column(Integer)
     created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)

backend/app/schemas/canvas.py

@@ -28,6 +28,8 @@ class NodeSave(BaseModel):
     ram_gb: float | None = None
     disk_gb: float | None = None
     show_hardware: bool = False
+    width: float | None = None
+    height: float | None = None
     pos_x: float = 0
     pos_y: float = 0
 

backend/app/schemas/nodes.py

@@ -27,6 +27,8 @@ class NodeBase(BaseModel):
     ram_gb: float | None = None
     disk_gb: float | None = None
     show_hardware: bool = False
+    width: float | None = None
+    height: float | None = None
 
 
 class NodeCreate(NodeBase):
@@ -56,6 +58,8 @@ class NodeUpdate(BaseModel):
     ram_gb: float | None = None
     disk_gb: float | None = None
     show_hardware: bool | None = None
+    width: float | None = None
+    height: float | None = None
 
 
 class NodeResponse(NodeBase):

backend/tests/test_canvas.py

@@ -191,3 +191,49 @@ async def test_save_canvas_hardware_fields_cleared_on_update(client: AsyncClient
     node = canvas["nodes"][0]
     assert node["cpu_count"] is None
     assert node["ram_gb"] is None
+
+
+# ── node width / height (resizable nodes) ─────────────────────────────────────
+
+async def test_save_canvas_persists_node_dimensions(client: AsyncClient, headers: dict):
+    n1 = node_payload(width=320.0, height=180.0)
+    await client.post("/api/v1/canvas/save", json={"nodes": [n1], "edges": [], "viewport": {}}, headers=headers)
+
+    canvas = (await client.get("/api/v1/canvas", headers=headers)).json()
+    node = canvas["nodes"][0]
+    assert node["width"] == 320.0
+    assert node["height"] == 180.0
+
+
+async def test_save_canvas_dimensions_default_null(client: AsyncClient, headers: dict):
+    n1 = node_payload()
+    await client.post("/api/v1/canvas/save", json={"nodes": [n1], "edges": [], "viewport": {}}, headers=headers)
+
+    canvas = (await client.get("/api/v1/canvas", headers=headers)).json()
+    assert canvas["nodes"][0]["width"] is None
+    assert canvas["nodes"][0]["height"] is None
+
+
+async def test_save_canvas_dimensions_updated_on_resize(client: AsyncClient, headers: dict):
+    n1 = node_payload(width=140.0, height=50.0)
+    await client.post("/api/v1/canvas/save", json={"nodes": [n1], "edges": [], "viewport": {}}, headers=headers)
+
+    n1_resized = {**n1, "width": 280.0, "height": 120.0}
+    await client.post("/api/v1/canvas/save", json={"nodes": [n1_resized], "edges": [], "viewport": {}}, headers=headers)
+
+    canvas = (await client.get("/api/v1/canvas", headers=headers)).json()
+    node = canvas["nodes"][0]
+    assert node["width"] == 280.0
+    assert node["height"] == 120.0
+
+
+async def test_save_canvas_dimensions_cleared_when_null(client: AsyncClient, headers: dict):
+    n1 = node_payload(width=300.0, height=200.0)
+    await client.post("/api/v1/canvas/save", json={"nodes": [n1], "edges": [], "viewport": {}}, headers=headers)
+
+    n1_cleared = {**n1, "width": None, "height": None}
+    await client.post("/api/v1/canvas/save", json={"nodes": [n1_cleared], "edges": [], "viewport": {}}, headers=headers)
+
+    canvas = (await client.get("/api/v1/canvas", headers=headers)).json()
+    assert canvas["nodes"][0]["width"] is None
+    assert canvas["nodes"][0]["height"] is None