feat(curve, waveform): add dap_parameters for lmfit customization in DAP requests

bec_widgets/cli/client.py

@@ -5973,7 +5973,8 @@ def plot(
         y_entry: "str | None" = None,
         color: "str | None" = None,
         label: "str | None" = None,
-        dap: "str | None" = None,
+        dap: "str | list[str] | None" = None,
+        dap_parameters: "dict | list | lmfit.Parameters | None | object" = None,
         scan_id: "str | None" = None,
         scan_number: "int | None" = None,
         **kwargs,
@@ -5995,9 +5996,14 @@ def plot(
             y_entry(str): The name of the entry for the y-axis.
             color(str): The color of the curve.
             label(str): The label of the curve.
-            dap(str): The dap model to use for the curve. When provided, a DAP curve is
+            dap(str | list[str]): The dap model to use for the curve. When provided, a DAP curve is
                 attached automatically for device, history, or custom data sources. Use
-                the same string as the LMFit model name.
+                the same string as the LMFit model name, or a list of model names to build a composite.
+            dap_parameters(dict | list | lmfit.Parameters | None): Optional lmfit parameter overrides sent to
+                the DAP server. For a single model: values can be numeric (interpreted as fixed parameters)
+                or dicts like `{"value": 1.0, "vary": False}`. For composite models (dap is list), use either
+                a list aligned to the model list (each item is a param dict), or a dict of
+                `{ "ModelName": { "param": {...} } }` when model names are unique.
             scan_id(str):  Optional scan ID. When provided, the curve is treated as a **history** curve and
                 the y‑data (and optional x‑data) are fetched from that historical scan. Such curves are
                 never cleared by live‑scan resets.
@@ -6011,9 +6017,10 @@ def plot(
     def add_dap_curve(
         self,
         device_label: "str",
-        dap_name: "str",
+        dap_name: "str | list[str]",
         color: "str | None" = None,
         dap_oversample: "int" = 1,
+        dap_parameters: "dict | list | lmfit.Parameters | None" = None,
         **kwargs,
     ) -> "Curve":
         """
@@ -6023,9 +6030,11 @@ def add_dap_curve(
 
         Args:
             device_label(str): The label of the source curve to add DAP to.
-            dap_name(str): The name of the DAP model to use.
+            dap_name(str | list[str]): The name of the DAP model to use, or a list of model
+                names to build a composite model.
             color(str): The color of the curve.
             dap_oversample(int): The oversampling factor for the DAP curve.
+            dap_parameters(dict | list | lmfit.Parameters | None): Optional lmfit parameter overrides sent to the DAP server.
             **kwargs
 
         Returns:

bec_widgets/widgets/plots/waveform/curve.py

@@ -22,8 +22,9 @@ class DeviceSignal(BaseModel):
 
     name: str
     entry: str
-    dap: str | None = None
+    dap: str | list[str] | None = None
     dap_oversample: int = 1
+    dap_parameters: dict | list | None = None
 
     model_config: dict = {"validate_assignment": True}